I think JabberJaw or SpeedBuggy would be pretty frickin sweet up on the big screen! They're already ridiculous enough to where you couldn't really ruin anything. Take Josie and the Pussycats for example. They kinda just made it their own in theaters. It worked.
Of course, I never liked Josie and the Pussycats myself. Honestly, it's a post for another time, but I am a HUGE Hanna Barberra fan, but I can't stand the stuff they made in the 70's. Except Hong Kong Phooey, of course.
I really gotta admit, i would have loved for Wacky Races to have worked out. Penciled in to play Dastardly was Dustin Hoffman. And if you watch his exact performance in Hook, you can totally see it.