In fact, come to think of it, wasn't there an experiment recently with remote-controlled rats, using plain Muggle science and electrodes in their brains? Extrapolate that forward fifty years and add those direct-to-brain conputer interfaces, and we could do something rather similar, given lots of training to get the feedback right. "When I think like this the rat goes that way..." An Animagus might learn this almost as a child learns to control its body.