The original design was made when I modified. one of their Phoenix revolver holsters to use the Safariland QLS system. The alteration was accomplished by unstitching the holster, adding the mounts, reinforcing the mounting area and then re-stitching.
It turned out really well and I sent them a picture of it along with the modifications I made. The mod allows someone to use ANY of the QLS systems for belt ride, mid ride or thigh rigs. This was about 14 or 15months ago. Anyway, I got an email advertisement from them for their "new" Big Iron holster. It is in my opinion ,essentially, exactly what I sent with except they used a slightly different holster (a modified DAO strongside as opposed to the phoenix). Its not a big deal but I am little salty they did not have the courtesy to mention using my idea.
In two of my pics, you can see the thigh rig, in the other you can see the mid-ride. I also have a belt ride for it. These also work with KT-Mechs universal system.