Passenger cars are also MIA.
Locomotives are another, odd story. About fifteen different kinds are still available new from Amazon, but as far as I can tell, there are very few of each kind in stock. NO consolidations, which is a shame. If you're thinking of a new On30 locomotive for Christmas, and you want any kind of a choice, get your order in now.
Here's the On30 home page from the Big Train Store. It's a little embarrassing how little there is on some of those pages.
http://www.bigtrainstore.com/on_30/on30.htm
But the locomotive page has a lot of variety, even if it doesn't have a lot of depth.

http://www.bigtrainstore.com/on_30/on30_locomotives.htm
Here's one I didn't list because I believe the stock is very low:
http://www.amazon.com/gp/product/B003VU ... BXMJAFIQQW