I've been thinking since you posted this question in your last thread. The speedloader holster would need to stay put in the pocket to have a quick consistent draw. Many pocket holsters have a small hook at the front of the holster to catch the pocket. If you enlarge the paddle you could accomplish this:

I imagine a large paddle of Kydex would be uncomfortable and print badly, so I envision the upper portion of this paddle made of a stiff leather. The leather is drawn in brown in the diagram. Even more of the paddle than I've drawn could be made from leather for a more comfortable carry.

The "hook" could likely be dispensed with if the outside of the body of the holster was covered with a tacky rubber substance like the Mika holsters, or, the side facing away from the thigh could have Velcro on it to hook into the pocket fabric.