Ok, I think this is all the dungeons/raids.
The first step is to work out which ones can be made in world (at their respective locations) eg ZG, AQ etc, and which ones need a seperated section and a warp. Things to consider are - how how/low dpoes it go, is there a real representation of it in the game (such as ZG, AQ..) or does it occupy a much larger space than available in game, (such as ICC or Ulduar).
After that, where and by who each will be made. I'm making a start (probably on Ulduar) tonight with a friend, will make it on own server and save schematic, at least until the world is up and location for dungeons is set. Tonight will probably be a LAN game but drop a line if you really want to be a part of Ulda team, I can support 3-4 players on my connection, nearly done setting up a dedicated server on a USA 50mb fibre friends line.
I have started work on a spreadsheet to help format and agree on where to build. I think some of Szes' might be a little optimistic for building in world if we want a good representation of the dungeon. All can edit the spreadsheet, I'll try to keep it backed up in case someone tries to mess it up.
Click for the spread sheet.