I like the Two-face Fozzie/Animal mash-up. I think that's my favorite:
Over at the blog Quinnarama, Quinn Rollins made some batman mash-up figures with Link Hogthrob and Dr. Strangepork (I like to call them Bat-hog and Ropork):
No nipples in these costumes (I don't believe that Muppets have nipples):
"Holy Mee mee mee mee, Beee mee!"
(Not sure who did this one so let me know!)