I Don't think it's possible to put the muppets in your bio. It IS possible to make a bioart , though. You can do this by either setting your language to Japanese and then editing your bio ( gives you access to characters that are not available on other languages
This question made me happy.. and then I was sad again when I realized I didn't have a good answer for you. I was actually looking at bio art today, you can find a lot just by typing "xbox bio art" into a search engine... however,
I haven't seen any that fit what you're looking for. Good luck and happy gaming.