Your next project. Bladetech IWBs are my current favorite. They're all Kydex, reasonably comfortable, lock up well and dirt cheap.
Also: Whatever holster design you go with should involve a "sweat guard" (prevents the top portion of the slide from touching bare skin).
It prevents uncomfortable chafing and serves as a retainer for your concealment garment (read: t-shirt) if you have time to hook it.
Your recent holster, for example, should have had the leather curve up to cover the rear portion of the slide.