Pete, the only newer engine made in large quantities from Rusty's list is the Lionel AF light Mikado. They are still available on eBay from time to time. I have 5 of them and they are great engines but there is no scale wheel option for them. They were the first TMCC/Railsounds 5 S gauge engines. In the pictures posted above the 1849 engine under the coaling tower and the PRR are two of my Mikados. The SHS engine shows up for sale once in a while. The two Gilbert engines, while readily available would need detailing work and a motor replacement to be appropriate for your layout.
If interested in small Gilbert engines the NKP 0-8-0 and PRR 0-6-0 are pretty good choices.
