I went to the Train Shoppe here in Salt Lake and picked up some of the new 18' cars by Bachmann.
Jeff at the Train Shoppe sells the cars separately, which is great for me as I just want to get a couple to examine and modify. The tank car is awesome. It is very low riding, more like real narrow gauge, but it is a bit hard to get on the track. The cars look great and have only limited lettering allowing me to customize it. They are weighted properly and roll nicely. I can wait to grunge this one up!!!
I only paid half of the price.
Here is the low side gondola in 18'. What a nice model! Once I get the shine off of it this will be a fantastic model.
Price seems to be a bit higher than the much larger cars previously made, but still manageable.
Here is a better write up in Model Railroad News: http://www.modelrailroadnews.com/firstlook-On30.html