Do the kids want to play kids? I remember playing TSR's Top Secret when I was 10-11 yoa, and my friends and I always played characters who were really, really old (like, twenty-one!).
Maybe a game about globe-trotting college students who travel the world with their cool, two-fisted professor, finding treasures, solving mysteries, and righting wrongs on a kind of extended 'field trip'. You could feature lots of exciting cliff-hangers and bloodless fistfights with smugglers and jewel thieves.
And don't forget the old gag where the crooks disguise themselves as a local boogeyman (the yeti, a sea-serpent, etc) to scare off those gullible locals, a plan which would've worked... if it weren't for those meddling kids!