Last I heard, they had already implanted embryos in Indian elephants and the pregnancies, which are twenty something months long, are in process. But it's just something I heard in passing recently so I wouldn't put a whole lot of faith in it. Still, it will be very interesting if we have a small heard of mammoths running around next year.
Wow, that's a hell of a lead time! Why not start with something smaller and faster? Even birds have a very seasonal reproduction cycle, why not start with something closer to a model organism. Are there any exotic and extinct rodents out there?