If you haven't checked his site lately, head over to Ragg's...To Riches? website where Joe's got a bunch of RGS-related kits in production (all limited run).
This includes a nice Placerville warehouse in HO, O and S scales.
There's also a couple of mines and a smelter building set (mostly in S scale), the Crested Butte depot (HO and S), and the Durango depot (S scale).
And the huge Rose-Walsh Smelter set in HO.