Welcome jeffr, as a fellow left handed shooter, I have adapted, ambi safety installed for my 1911 but still have to adapt to the slide stop, but did find great success from the S&W M+P .40, which is great for me; finally,
some pistol manufacturers are realizing that.
HK's have always been top shelf, tried and true, as long as nothing ever goes wrong with it, it's a rare occurrence, but their market is large LEO, International Military Contracts. So as citizen consumers, we are just at the end of the line.
For IWB holsters.
So many options, here's another variety.
http://www.comp-tac.com/catalog.php?cPath=28&osCsid=p472aaqa44tvilr5plu663smq3http://brommelandgunleather.com/Plus, Andy, as posted before, would be glad to make one to spec. I don't think he's as backed up as Milt Sparks but,...
For my M+P, when it's not 90 degrees, I have the Infidel model. Seemed appropriate..

Sits low enough to conceal under a button down short sleeve shirt and still sit and drive comfortably, and angled enough to make drawing a natural grasping motion.
I wear mine alittle further back like between 7 + 8:00 position. Your mileage may vary.
Post a picture, or share what you decide to get. Glad your here.
tw