D1 Tark is a bit different animal in regards to the Mountain West. There's really only one conference out that way: PAC-10. Near half the PAC-10 schools have been empty for many seasons. I don't mean to diminish what Chief has done at BYU, because he's been awesome there. But its a lot easier when half of one of the power conferences is empty and not raiding your recruiting area.
I don't keep hard core stats like others, but I can say that I'm fairly positive the last 3-4 teams to win it all in Tark were 800+ rated. Some of those teams had 3-4 freshman on them or walkons. I lost in the second round to a Rutgers team I looked at and decided not to bother game planning for. And I had a 750 rated squad and felt I had no shot to win. Really, 800+ is the standard at least in Tark to win it.
The current top 5 in Tark is
814 (UCLA, lowest rated player 699)
786 (Texas AM)
719 (Rutgers, defending national champ, 2 walkons)
784 (Kansas - one senior)
790 (Stanford)
Somewhere like BYU where its too far west for 5 of the big 6 conferences to mess with you, and half the Pac-10 new or rebuilding, has a shot. Otherwise, its an extremely painful climb for someone on the east coast where 15k+ is rolling at you from a power conference, plus prestige.