Bianchi 100 Professional Inside the Waistband Holster Colt Pony
I'm not 100% sure exactly what floats your boat but after thinking about it I looked up a few. I have a DeSantis pocket sleeve for mine and haven't tried anything else.
What about a fancy leather shoulder holster? Wouldn't that work similarly to your cross draw method for car carry?
If you want it so you can draw while seated,like in a car, look at the Galco Miami shoulder holsters. They are really comfortable but they are pricey. This is you best option but a shoulder holster is about the best for the seated position.