I don't have very many D20 books, but I do have a few.  While thumbing through Green Ronin's Ultramodern Firearms I remembered a post here where someone talked about a big mashup of various rpgs in his D&D world.  This got me to thinking if it would be possible/workable/desireable to mix up D20 Modern, D20 Cthulhu and D20 WOD (for the crunch).  V20 could be used to add VTM aspects to the game/world.  

It sounds kinda fun in to me.  You could have Delta Green type games, VTM WOD games plus , Hunter vs Mythos games, WOD vs Mythos, nihilism, grimdark and cosmic horror.  You could even toss in 3e proper (or Trailblazer) and have resurgent Cults of Templars or whatnot.  

Anyone ever try this?

No, but I've thought about it a lot. My problem is that I never got to be much of a 3E/d20 fan, so while I have a bunch of the books I don't do much with them. But I have considered putting a bunch of this together.

Your list of cool d20 books was nice, but you forgot the d20 Dark*Matter book. That would allow you to throw in UFOs and conspiracy theories into your Cthulhu/WoD campaign.

I'm not sure how miscible D20 Modern is with the other stuff. Maybe some of the feat ideas (it's been a while).

My suggestion would be to take one modern game and then dribble in cool things you like from other games, rather than a more ... hybridized thing.

(Also, another D20 to consider is Spycraft. I found it way too detailed for me, but...)

Thanks for the tip on Dark*Matter. I'll have to check it out.

It looks like Cthulhu and Delta Green make a pretty complete game, the other stuff could be bolted onto the framework me thinks.

This feels a bit like getting excited about DVDs in the Blueray era.

You mean they are smaller than Laserdiscs AND you don't need to flip them?!?  Wow

Hmmm, seems like the microlite guys have already done the heavy lifting. Now you can have a small packet of papers and then use the setting material separately or on a much lighter pdf.

http://www.retroroleplaying.com/content/microlite20-rpg-collection

Choices choices.

The only d20 I willingly GM is d20CoC. The same goes for playing. Otherwise I don't find d20 mechanics and play style to be amusing enough to spend time on.

Why mash all those games together with d20 when there are so many easier systems to do kitchen sink gaming with?

Funny, I was going to say I didn't think the D20CoC rules were actually that GOOD (although some of the non-rules writing was really excellent).

Another option is a stripped down M&M, but that might be tricky.

Well, at a cursory first glance they seem to be interoperable.  Keep in mind that 3.5 WOD level 1 PCs are at about level 4 in D20 M.  Using d20 modern or microlite d20 allows one to have a game where you sneak in horror elements. For example:

Blah blah blah, you break up some illegal fishmongering ring or whatnot. As you start looking into the exotic seafood/sushi, boom sanity check!

Or

After fighting a biker gang speed freak drug dealers and having a Tpk at the end of a session. Turn in your character sheets and we'll roll up new ones next week. But, next week you do not get new toons, you get the same toons but the welcome to the kindred speech.

Anyhow, it seems kinda cool. What kitchen sink systems do you think would be better?

Cheers!

Also- Dark Matter d20 seems unavailable online legal or otherwise. I might have to spring for the Amazon plus the slow boat to China.

D20 really isn't that great a system for bashing things together. Part of the problem is its enormous power curve. It makes things hard balance. D20 games tend to rely on lots of moving parts, like feats and prestige classes, which can interact poorly. This is magnified if you mash a few D20 game together. It's just a really hard system  to design for. Even WotC had trouble with it, let alone most of the third party stuff.

Looking at the games specifically, CoCD20 is okay. I've run it. It works, but its at odds with itself. A lot of the rules are there to counter things the system does naturally. You have exploding hit point accumulation, which the game keeps from D&D, buy you also have the clunky massive damage rules to try and counter the inflationary hit points. Wouldn't it have been easier to just do away with inflationary HP?

I didn't like the removal of the MP economy. Spells just cost sanity now, which means for NPCs, they cost nothing. Gathering MP for big spells used to be a good motivation for NPC plots that players could thwart.

Once again, its not bad, but I see no reason to actively choose it.

D20 Modern is one of the better iterations of D20, but I find that pretty faint praise. I don't see it interacting well with CoC D20. Will is right about the non-mechanical parts being excellent though. It's one of the few D20 books I still have on my shelf.

If you are set on using D20, definitely follow Will's advice and lay one version of D20 down as a base to run off. Then slowly and carefully add bits of other games. D20 is a system you can easily fuck up just by applying books from the same game line, let alone other game lines.

As for other systems. GURPS is a game that actually does work well with just mashing its books together. During 3rd edition, it even had officially-licensed V:tM, W:tA, and M:tA books, and has rules for Lovecraftian stuff, as well as government agents and conspiracies. If genre-blending is a thing for you, this is a good system for it.

BRP is another reasonable choice, being the home of the original CoC. While I really like BRP, I find it does grounded stuff better, and I am not sure that is the tone you are going for.

I find that a good many of the detractors of d20 CoC have never actually tried playing it. They just "know" it must be bad.

That is not to say that the game doesn't have warts. It does, and some are rather large. The inflationary hit points/massive damage system is one of the larger. It can be fixed, but shouldn't need to be if the game were better designed.

D20 CoC is one of the earlier adaptations of the d20 system and it shows. Lots of rough edges, but at least it is a stand alone book. It is head and shoulders, not to mention knees and ankles, above "Dragon Lords of Melnibone" which is an unplayable mess. The only reason I still have my copy is for the art from European Stormbringer products I don't have.

GURPS is a good system for genre bashing if you like the system, I don't but still find the sourcebooks generally excellent resources for any game.

BRP, Legends, or OpenQuest all offer versions of the system at the core of CoC and have numerous different genre books and supplements that could form a good platform.

If White Wolf had ever released a generic core rulebook for Storyteller (WoD) that might be a good system too.

If d20 doesn't offer enough K3wl Pow3rz there is always Palladium Books... They have Lovecraftian nasties, modern, Vampires, Zombies and more spread through out their games. Beyond the Supernatural even has some good ideas buried in it. We had fun using it as the base game for a couple of sessions, but Palladium characters tend to get very wonky very quickly.

Contagion 2nd Edition tries to do a lott of that, but without the sanity points.  I'm not sure if the system itself is a mess because I've had a difficult time trying to take in the 612 page rulebook.

Thank you for the suggestions everyone.  I think D20 Cthulhu+WOD+Dark Matter may be possible, especially when using a base of Microlite d20 Modern or one of its variants and could be pretty cool.  Like many others, I am not a fan of feats, big skill numbers and prestige classes, but a stripped down system could work.  

Another option to go with OpenD6 or Mini Six.  Free versions of the Fantasy, Adventure, and Space rules are available in addition to the Mini Six Barebones ruleset (among other small expansions).  D6 Sanity rules have already been created here:

http://www.ruleofthedice.com/2011/05/how-i-put-crazy-in-my-game-sanity.html

and applied here to Mini Six:

http://www.ruleofthedice.com/2011/07/mini-d6-horror.html

Dark Matter setting material could be used, while creatures and such could be converted from D6 material or on the fly.  

V20 could almost be used as is 8,9 and 10 on a d10 track pretty well to a 5 ( and 6 (9 and 10).  This may or may not work.  And least the setting material is rather complete in the compiled pdfs and books.

I have an aversion to Gurps and Palladium, but that is my 90s bias showing.  CoC proper (and I guess by extension its offshoots) is not too exciting to me, but perhaps I need to give it a go.  It has been a long while.  

Cheers!

Another option that is legally downloadable is the True20 Cthulhu book titled Shadows of Cthulhu. Anyone have thoughts on True20 as a kid Chen sink system. Can d20 material be converted on the fly with T20?