BTW, I am planning on Simpson's vs. Southpark characters.
That's a cool idea. The only stumbling block I forsee is that foosball men are generally all the same height while, if you use the relative dimensions of the cartoon characters, they'll be quite different. For example: Cartman, Kenny, Kyle, Stan, Bart, Lisa, et. al may be too short (or too wide if you make them all the same height). If you make them all the same dimensions, some characters may look out of whack (i.e. like taking a 300X400 pic and resizing it to 600X200).
Anyway not saying it's impossible, just something I was wondering about.