I seem to recall a deal made by Celador and that great cartoon company Dic (Inspector Gadget, Super Mario, Sonic, Real Ghostbusters) to create a cartoon version of Millionaire which had contestants collected their winnings and continue from there. However as of yet there is nothing new.
My guess is that they canned the idea due to what the Saturday morning market has in store for the youngins. Turn on the TV at that time and you have mostly live-action programming (NBC, Power Rangers on ABC) or cartoons involving duels between monsters owned by the show's characters (Pokemon, Yu-Gi-Oh, Digimon, etc.). The market seems to be aimed at pre-teens, a group who probably could care less about what a cartoon version of John Carpenter or Kevin Smith did with their winnings.
I remember hearing about this also, and my reaction then was about the same as my reaction now: It really seems like a stupid idea. Besides the "not caring about cartoon version of x", a show based on the entire concept of consuming, though perfect for a Saturday morning series, would get real old real fast. Unless they had two winners from the show using their winnings to develop the ultimate duel machines, and all done Anime-style, I doubt it would be viable in the market.
John Carpenter: Kevin Smith! I shall you use my IRS-Bot to crush your machine and vigilance!
Kevin Smith: You are incorrect Carpenter! My bot will never be defeated!
<Staredown between the two combatants as a music sting plays>
Then it goes into commercial. The battle will take place over three or four episodes, a la Dragon Ball Z.
Wow, one more post to 100. Wheeee.