A light compatible kydex holster does not use the trigger guard as the retention mechanism. So what you're asking for is a full on kydex shell (all the way down to the light) with leather backing. I do believe there is a company that makes this sort of thing right now...but the name escapes me.
Another option for carrying IWB with a light: RCS sells IWB loops for their Phantom Modular Holsters, but it's a lot of stuff to be stuffing inside your pants. A quality light compatible kydex holster (RCS, FogHolsters) holds the weapon tight to the body and is perfectly concealable under a shirt OWB....that's the direction I would go (and do go) when carrying with a light. You'd be more comfortable concealing OWB. JMO