I understand the idea and have seen a couple different versions including the sneaky pete (leather) and PdaHolster (nylon). I think that something that is nylon is slightly less noticeable if you are doing some activity like running, at that point it could be a med pack or whatever. Some of the issues that I have seen are design vs. being able to draw and the addition of a buckle to keep them closed. Any buckle will inhibit draw in my opinion, a strong magnet or snap (as the one you show has) is a better idea, or maybe velcro. The other consideration that this type of holster needs, for people running/biking is a spot to put a CC permit or key. PdaHolsters says they add a spot for a pen holder because that makes people think it's functional vs just being a holster. I guess that's a start. The ones you linked I believe are rough drafts? It looks like the fit and finish could be worked on a little. Anyway thanks for the heads up.