When I was shopping for saddles (and it was SHOPPING: I tried 7 different stores and about 30 if not more saddles including TexTan, Tucker, Circle Y, Alamo, Bill Cook, Abetta, Big Horn, and some others) I found only 2, which would fit my high withers narrow back paint: one was Alamo pleasure saddle (I tried several models and only one I really liked) and Billy Cook saddle, and would feel comfortable for my bum :) . They both have high pommel with enough clearance for the withers. I ended up with Alamo and it works on my paint as well as my wider qh.
Also I know people with high withers/narrow back ottb who found Big Horn (which is cheaper I believe than Alamo or Bill Cook) to fit him.
What I really do NOT recommend is getting those flex-tree ones. They didn't fit my horse for sure ending up on top of the withers (even though the salesperson said it's OK, I personally don't believe so).
Frankly, if you really want to get comfy saddle you better look around in different stores and try them first on "dummy" horse and then may be borrow and try on your horse. We all have different tastes, so, for example, I may recommend you something you won't like. :P