I'm not sure why the Sabres would trade him. They have no one in the pipeline who can replace him. Unless the team wants to go into complete rebuild mode. Even if they do that I still don't know how they replace him.
I doubt it, but who really needs a goalie bad enough that could give Buffalo some nice assets back? Edmonton? Philly? The market for goalies is going to nosedive with all the ufa goalies plus Vancouver's available.
If this does happen in the off-season, I could see Detroit making sense. Miller has his Michigan connections, and with Howard a free agent in the off-season, he could replace him. But that's very much just skimming the surface of a place that COULD make sense. I don't know if Detroit isn't keen on adding more older players or if they're looking to go younger. I'm not sure if Detroit could/would offer up the mammoth offer it would take. And Buffalo may not want to trade him to a team joining their conference next season.
I'm very wary of a Miller trade happening; it could, but I just wouldn't expect it. But if he really is available, I could see Detroit as a possible match.