I finally got an Emacs running on v7--it's on misspiggy at LCML now as "ue".
It's Microemacs 3.6; what I did was to clone https://github.com/troglobit/MicroEMACS and check out the first commit. Some experimentation later, it had the usual problem with v7 and DEC linkers that not all the function names (er, more generally exported symbols, but in this case, function names) were unique in the first 7 characters (which is 6 if you're working with DEC OSes). So a bit of sed later and I had something that built, linked, and appears to run with TERM=vt100 set. Arrow keys, naturally, don't work, but C-b, C-f, C-p, C-n do. I think I'm going to just make a GH repo of it, but I'm happy to send the tarball, or tar.uue, upon request. I find UUCP kinda fragile on my simh installation, and I don't know how to get to Miss Piggy's (although the uucp commands are there), so, well, uuencoding, a pasteboard buffer, iTerm2's "Paste Slowly", and cat will work as a file transfer mechanism. Now I'm going to run over to TUHS and announce the same. Adam