It's been 3.5 months, I've not been able to find a single piece of ATSF rolling stock - scale or hi-rail. When they've popped up, they sell before I have a chance at them. When they sit, it's cause someones asking twice market - and they will get it given the lack of availablity. I guess that while there aren't enough bodies out there for the companies to justify building stuff, there are a ton of scavengers picking at the carcass. Back to the drawing board for me.
Are you looking for a particular brand of product, era or car type? As Tom and Rusty note, plenty available direct from AM and Port Lines. Plus Pikesville Models, the other S-only online retailer, has quite a few.