I've gone through quite a few holster choices over the years, in no small part due to hiking comfort (or lack thereof.)
The Serpa was my #1 go to for a long time, in paddle format, and it worked great. Comfortable, extremely secure, durable, etc.
Then I discovered the joys of backpacks with waist straps. Soooo, on to a Blackhawk Serpa in a drop-leg rig I went. That worked better for times when I was using a waist strap, although due to the thick belt I use (Wilderness Instructor belt) I found that having the weight of the gun pulling down on my right side, combined with the waist strap compressing the belt into my flab, it would actually start to get really uncomfortable over anything but short trips (which ya generally don't do when you're carrying a full size pack and using a waist strap...) The Blackhawk Serpa + drop leg combo also kinda sticks out a good bit, and gets even worse if you use the quick-detachment plates which I do.
Then I got lazy and got back more into day hiking vs. backpacking, so paddle holsters became an option again. Since then i discovered Safariland and can't say enough about the quality, fit and finish of their holsters. I'm particularly fond of the Safariland ALS thumb-style retention release. It also covers more of the gun and protects its finish than the Serpas do. http://www.safariland.com/DutyGear/prod ... x?pid=6378
That then morphed back into the ability to wear it with a waist strap backpack, and being a Safariland convert, I had to see what they offered. They do have standard drop-leg platforms, but not being a huge fan of those, I kept digging and found this gem.
http://2.bp.blogspot.com/_1SUWtQ-SXvk/S ... rs+003.JPG
It's basically a high-riding drop leg platform (using their 'drop flex adapter') that keeps the whole rig up high and close to the body. That eliminated the other issue of the gun being lower and causing a little more fatigue from swinging back and forth with every step, but it also helps with keeping it from getting banged around on rocks a good bit. It doesn't really eliminate the 'pressing into the flab' issue too much, but I'm slowly learning that that really isn't avoidable with such setups. All the Safariland stuff is modular, so you could take the holster itself from the first link off of the paddle, mount it to the drop flex/leg adapter, or get mounts for vehicles, molle webbing, etc.
I also did the Safariland Safepacker thing for a very short stint. It actually can be a pretty quick draw if you mount it to the waist belt of your pack, but it can also flop around a little too much for my taste, especially with heavier sidearms. I refuse, however, to have a gun mounted to anything but myself. Having it attached to a pack strap would mean never being able to set the pack down without undoing the velcro connection every time to take the setup with ya. The Safepacker is fantastic for in-hand carry though, or throwing it in a pack (although that kinda negates even having it.)
As for being covert, I agree with beterarcher. I couldn't care less what other people think. That's their problem. Sure made for some interesting conversations on past backpacking trips in the Grand Canyon though =)