dnseibold:
We offer "custom" work and for a very reasonable price. I'd welcome the opportunity to answer any questions you may have.
With respect to the Pocketholster.com design you mention, IMO it interferes with function. You've got to take an extra effort/physically move that "zipper" portion out of the way in order to then slide your hand in to get a grip on the gun. And if your pants are tight/snug in that back pocket, you're going to have an even greater struggle doing that.
We made something very similar to what Pocketholsters.com offers. In our version, you had material which covered the backstrap. You only had to push downward, in the same motion as acquiring the grip, and it caused the material to move out of the way.
That being said, I would suggest you buy pants which have pockets deep enough to help cover what's in the back pocket. A little bit deeper pocket makes quite a bit of difference. And if anyone is able to see the backstrap of the gun, then IMO they're standing way too close for my comfort, and I would be moving away from them.