Back in the first decade of the 21st Century,
Panzerschiffe (maker of mostly military resin-cast items) bought out Ultimate N Scale's stock and molds.
Back in 2011 I purchased several ex-Ultimate N Scale resin cast trailers which were in-stock at the time (I still have most of them). Even back then, when I asked when the out-of stock models would be produced I was informed that Panzerschiffe was not planning on producing new models but just selling off the remaining stock. At least that is what I remember.
These are pretty decent resin castings, but as Bryan mentioned, they seem to be larger than N scale. Our own
@Rasputen could likely made shrunken copies of the Ultimate N Scale castings to proper N scale size, but even if he was willing, Panzerschiffe would have to give permission to do that.