I have actually started working on the design scheme for a Lord of the Rings (well... basically Middle-Earth themed) EQEmu server, and you can find the (crappy) webpage at
www.sypherion.com/me-emu
If you're interested in helping out, if you can code, or design webpages, or have ideas for development, or quests, or really anything, please email me at
hamled@trifocus.net.
Also, about adding new zones, I'm not sure if what Killspree said is totally correct, however I do know that creating new zone models, or editing current zone models, and having EQ still use them will be very hard. Currently we don't know the majority of the format for the zone models, so it'd be like trying to write a book in a language you only know a few words in.
And in repsonse to Darkyth, the emulator will never be completely finished, as all we can really do is try to keep up with the latest things that SOE comes out with. And so, the present is probably the best time to start working on a project. It just means that we will have to code very carefully.