Pax, have you held/used/tried a Blade Tech IWB? I have thought about bonding a backer material to mine to make them a little more comfortable since I like the holster so much.
Mark Miller at Mach 2 Tactical custom makes kydex holsters and accessories. I have not seen anything with leather or fleece but I think he would be up to the task if you asked him to.
http://www.m2tactical.com/