ThinkPad with pen input that uses the old ultra dock?

I have the last mechanical "ultra dock" (40A2 series) that connects to a docking port on the bottom of the laptop, which I bought recently for my X250. If I were to replace this machine in the near future, it would be nice to get one that is compatible with the same dock.

Unfortunately, this is between the X220/230 tablets, which predate that dock, and the recent [Thinkpad X/L### Yoga] variants, which only work with newer (usually USB) docks. I also looked up several Thinkpad Yoga and Thinkpad X1 Yoga models from around the right time period, but no luck.

Any other ideas?