Never coached Arizona, but coached A+ Kansas and based on that I've said multiple times that I feel Kansas is the toughest "traditional elite" program to recruit to with the probable exception of Arizona, due to exactly what you are saying. The way we do recruiting it is tough to fight for multiple top-level recruits at long distance. For the scenario you describe it may be even worse than I saw, in that I did fine going west into say Utah to find some kids, but with a strong MWC that is much tougher to do effectively. I felt Georgia Tech--even at lower prestige--was much easier to recruit from because quality recruits are so much closer, and the recruiting is driven so much by distance (and the associated cost) it seems.
Now, that all said, I don't think leaving Arizona is necessarily a great idea. It may be tougher to get the kind of recruits you need to meet or exceed expectations, but unless you have a program in mind in an area which has weaker Big 6 conference schools close then you will still be struggling to overcome the prestige differential, and probably doing it on less post-season money (since it sounds like the PAC-10 is strong). For the right situation you *may* get it to work out, but I'd think twice before I left A+ Arizona.
Maybe you just need to shake things up recruiting--be a bit more of a opportunist, hold some schollies / cash in reserve and exploit where further out schools overextend. Maybe even try a true "poaching" approach, and hold all effort back until late and jump in hard with both feet. You may be like me and that is not your natural "style" but to break out of your old rut you may need to force a different style in and try it. Food for thought...