I too end up wearing my long-johns (fleece lined even) under my jeans. And when that no longer cut it, I broke down and bought a pair of chaps with removable insulation liner. The chaps, while adding some warmth, was mostly to keep the cold wind from the skin; therefore, somewhat warmer. I've been quite ok with that combo and generally don't ride below 35ish.

If you're looking for just jeans, one of the guys I ride with picked up a couple of pairs at Bass Pro Shop, one was fleece lined and the other was flannel lined. That raised my eyebrow and I look to get a pair of each myself.

2005 America, green/gray, gutted stock pipes, tall sissy bar w/ luggage rack, Saddleman's dual touring seat and Tourmaster saddlebags (and sissybar bag).