I haven't had time to do a search on this one so forgive me if it has been posted already...
Okay, we all know how difficult it is to remove the latest mirrors on F150's and the like even with the supposed "Ford Mirror Removal Tool". I was working on a clients old Cadillac Alante (remember those?) and during the conversation he told me how he was able to remove the mirror on his F150 with little or no effort.
I haven't tried it but I think i would have to work.
He sprays some WD40 on the windshield where the mirror is mounted to it. He then heats up the mirror from the inside, which causes the metal to expand ever so slightly and loosens the mirror from the mount that is attached to the windshield. The mount does not get nearly as warm as the mirror so it just slides off!
It sounds very likely that this would definitely work. I'm trying it next time