I would love to see another Speed Racer game, based on the 1960s anime (face it, that SNES version didn't count).
I'd like it to be a Racing/Action Adventure hybrid, with fluid animation along the lines of Marvel Versus Capcom 3's character intro video. It would have stats/ level up points that seem to be the trend these days, and allow you the ability to upgrade your car as the story progresses.
Great idea for a Thread too, OP. It can't hurt to throw ideas out there. I remember wishing for a Scarface game on a message Board years ago, and I'll be darned if it didn't eventually come out like 3 years after.
Remember, video game designers read Message Boards too.