I know many of you wouldnt want to try combining riding a horse and shooting an AR, but i wanted to know if anyone knew of a holster that would go on a western style saddle.

I tried to find one for an Ar to put on my dirtbike. All of them I found for lever actions, shotguns and the likes. I ended just making it.

I had an old shotgun scabbard laying around that was for a pistol gripped shotgun. I cut the flap off. Split it down the spine cut out a square for the magwell so the rifle/carbine would fit a little more snug.

Used some of old nylon straps with buckles to secure it around my seat. It sits far enough back I can put it upside down(so the weight of the magazine is not hanging free weight) and carry it with a mag loaded. I'm sure a holster maker could build something out of leather real easily.

Ted Blocker's in Portland, Oregon (www.tedblocker.com), does custom holsters and leather for tactical and western shooting - I know they're personally very involved in western competition shooting events.  I'm sure they would be able to build you something.  

I've never owned any of their stuff - I'm a Galco fan, but I've been to their workshop and can imagine they'd be able to help or at least point you in the right direction.