Only in the movies lol, Jim Henson lol
I have my own idea for that... I'll give a description.
Xile's kinda strange but-makes sense otherwise turtle shell idea:
I envision the turtles having the ability to retract and extend their shells from their bodies - kinda like wolverines claws. And eventually I wanna take the term "mutant" and stretch it out more - that they would be able to grow instantly and retract instantly on any part of their body a turtle-shell armor that can strengthen them when they fight or travel into strange territory.
Yah, so that way they can wear clothes and stuff and they don't look fat XP