I've only worked on 2-3 editors, my first being a port of the Yale Z (pronounced "zed") Editor to Tulane's DEC 2060 minicomputer running TOPS20. That was largely an adventure in learning Bliss36. I was next involved in developing the Tulane Z Editor running under VAX/VMS, entirely in a VMS dialect of K&R's C Programming Language. I currently use Z, Emacs, and vi running on all manner of Unix systems. Some of my personal revisions of Z included rather strange features, e.g. I once had a version that allowed me to "edit directories" in a "full screen" mode. By "editting" I mean that this feature allowed me to rename directory entries [Term Paper], change file modes, copy and link files, and even change the modification and access times associated with entries. I decided this wasn't the most useful feature in the world, and created some disturbing potentials for ambiguity in the filesystem though, so I dropped that a long long time ago.
My primary focus is not the development of editors, but other types of systems and software, for which I prefer my own hand-rolled programmer's editor to those that tend to be distributed with systems. The software I've been involved in writing includes C/C++, Java, and PHP compilers and interpreters, software tools, networking systems and software, security software (multi level secure systems, firewalls, and crypto systems), embedded systems, custom apache modules, and all sorts of system service utilities. I'm also currently leading Team FREDNET, a Team competing for the Google Lunar X PRIZE using an entirely Open Source methodology.
I can be reached in the usual ways, though I always hate listing email addresses on web sites. Try a google search, it is pretty easy to find me.