Boredom led me to a thought..

I don't see why not - all it is, really, is a shaped shell around the mechanical parts.

If the animal is lying down, and has a fat belly, then you could even have a slot-loading drive, and a built in Hard Drive that you can upgrade yourself (much like the PS3 with its PC hard drives), which gives the added advantage that you can use animals such as cats, which have small heads and largish bellies.