I personally wouldn't stop rooting for the Bills in such a case, especially if it's just the name that's changing. What's in a name? I haven't actually lived there for 6 years and my interest hasn't exactly waned.
A relocation to Toronto or beyond, though, and I might have to shift the focus of my masochism to Cleveland.
EDIT: I still don't think it's going to happen, though. I've yet to see something more substantial than "Based on my limited understanding of the markets involved, it seems sorta logical."