I just saw there is an ME11 Memory Expansion unit on eBay (not mine), stamped 'M11'. https://www.ebay.com/itm/114941479208 Until seeing this one I had not heard of any other units out there apart from the one I recovered (ex-BHP steelworks) a few years ago. Mine was connected by a flexprint cable to a rebadged PDP-11/15.
If anyone here ends up with it, I have an OpenSCAD model of the Mazak bracket p/n 1211221 that holds the regular 5-1/4" DEC fascia panel onto the front of the H-909 cabinet this unit uses. This is the same cabinet as the slimline PDP-11/05 and to be honest when I found the ME11 that's what I thought it was, and that the console and CPU boards were missing. I then found the fascia panel with the original brackets close by, and it fitted exactly. I've printed a few from PET and they work as well as the originals (including the threaded hole), so I could do a few more for whoever gets the eBay one should they want them. I am slowly scanning the ME11 print set too as I've not found any online copy out there so far. Steve.