Stress_Test said:Thought about a belly band (?) or something elastic but wouldn't trust the gun and everything to stay put when running.
(OP, sorry for thread drift... but I think the original topic is pretty well covered right?)
You might be surprised what can be achieved with some tweaking. The Galco Underwraps is pretty darn good for anything short of sprints.
Using a running style like pose running helps since you smooth out your gait a lot.
If flopping was an issue I do know of one definite way to solve it. Grappling shorts are made with a very strong elastic band that secures two different ways with velcro, plus a draw-string.
For example I have a brand of shorts called Fighting Sports, made for grappling. They would work fine for running - very cool, wicking, quick-dry material, and some spandex sections for mobility (along the sides). Also built very tough.
They really help concealment as well as retention using a belly-band. If you really wanted to make concealment work, I can almost guarantee that a belly band plus grappling shorts would work for running. But you can't know if you don't try!