I know what you're talking about - I've read the forum ;-)
There used to be a project called Sauerville, which did this .. but it was heading for an RPG style of gameplay and anyway is defunct now - it didn't use CVS or SVN but merely a webinterface for uploading.
I'm pretty sure you're just after the effect and not married to the method.
Feel free to keep updating this post with whatever people send you - hopefully you'll give them full atribution.

D: where is the download link?
I want to help!!!

And you have to make some rules about what other ppl can edit and what not. The main reason for this is to prevent double edits on the same map area.

For example: Is the hotel only yours, or can other ppl build there stuff in it?

And we also need your e-mail address if we go the way "MeatROme" has suggested.

here is the link:
http://yellowprotoss.ye.funpic.org/website/sauerbraten/hotel-frenchn00b.zip

Cheers / Greetings !

("frenchn00b linux",and you'll find me...)