I've given a new design a lot of thought for quite a while but I have ZERO skills when working with my hands, so....
I think a kydex holster with "J hook" loops fore and aft of the body, fat flap (commonly referred to as a "body shield" or something silly, face it, it is a FAT FLAP that keeps your FAT from flopping all over the firearm!) and a slight gap between the body and the hooks to allow the holster to be worn either inside the waist band or outside. Actually I've drawn this up somewhere but never developed any interest from anyone.
Also have another idea a Sgt freind of mine and I put together; This one is a removable holster that would go either strong side of crossdraw very easily. The belt mount is similar to the mount on a streamlight tactical light and the holster has the picatiny rail or male side of the mount. The holster is designed to be used by those of us with the exciting, exhillerating job of surveillance, cold coffee and stale donuts - gotta love em. you kind of need crossdraw when you spend the majority of your day, or night, seated behind the wheel of a car in some seedy neighborhood in an alley. When we exit the car we want the firearm in the right place, strong side hip. So why not make the holster quick detach like your tac light. Safety is optimum because you don't need to unholster your firearm to move it, but it would be much more comfortable than a paddle holster... Which I can't stand!
See, you should have pity on those that watch the night for 10-16 hours at a time, this is all we have to think about! I've actually got a couple of other ideas about holsters, specifically a retention holster very loosely based on the bianchi carry lock but with a much more positive/natural release that won't effect your grip prior to the draw....
CA PI