I just talked to a T-Mobile rep today and asked her about it, she "looked it up" and said that they showed an availability date of April 15. It was still uncertain if the phone would be eligable as an upgrade, but that's the news I got.
I can't friggen wait. My 7100t is just a piece of junk now. Staticy calls, disconnects on dialing out, volume sticks... I WANT MY 8700!