Sorry, I must have missed that. Everyone seemed to be focusing on Psylocke.
One other SA hero that I personally didn't think of until just now: Hercules. I know that drgnrbrn316 ruled him out, but I'm not really sure why. He's a definite Silver Age character (he first appeared in an early issue of the Avengers), he has his own series and he's never been a Minimate before. I'm still going to go with the Panther (I think DST realizes that there is more of an outcry for the Panther then Herc), but you never know. Or not until tomorrow, at least.
That weird I also guessed Hercules, but I agree a black panther does seem like a better deal,but like you said we find out tomorrow!