I have two 1392980 Space Saving Terminal Ms, and have been looking into a method to get them outputting AT or PS/2. From what I've read, it seems that Kishy's terminal hacks might work, or that I could optionally swap out the controller from a PS/2 model (although I'm unlikely to find any donors).
Can a normal M controller function inside of a space saver?
I may just keep them boxed until a USB board is available.
Here are some pics for the curious: