Cake - Not wedding

I would be interested in a simpsons themed cake. Originally I was thinking that it would be cool to do the couch with them sitting on there but then I realized it may come out too big. Its for a small gathering we´re doing for FH. It will be max 20 people. I would like to incorporate at least Homer, Marge and Lisa somehow. If anyone could give me approx cost and any ideas I would greatly appreciate it.

TIA