Yeah, it's possible. The 2 guys you mention had great runs to get a ring, I believe they have been the 2 exceptions to the rule.
If all other things were equal between a 6-3" to 6'4" QB prospect and a 6-6" QB prospect, I'm picking the shorter guy each and every time, and a 6'7" and up prospect never. Tyree Jackson makes for a nice local story, but I think having him on the Bills is a waste of time.