My view regarding the ethics of such a thing is that as they were extinct already, any life that we gave them, whether it be the crappiest jobs that are hardest to fill, rooting out terrorists from cave systems, or fulfilling vital medical experimentation, would all be better than their current situation, and when we had solved all our major problems, we could even consider giving them rights, and allow them to live in society as equals. Surely its got to be cheaper than devolping humanoid robots?
Objections, anyone?