Brain and Head transplants have been done with monkeys by Dr White - formally of Case Western. A human would in fact be easier than a monkey - because the stature is larger.
"All over the world there are lots of brain dead people with healthy bodies, and brain alive people with virtually dead bodies; and there should come a time when one could match them up and make two into one.”
You could for example take stephen hawking and put his brain into a perfectly healthy body.
An interview with Dr White
BBC on the ethics of this