The ones I've seen for Morrowind are really nice as well; mainland Morrowind (as part of TR), Cyrodiil, and Black Marsh. There might be others, but I haven't seen any.
Eventually, maybe the whole of Tamriel could be created in both games! I do wonder though, if it really happened, which game would you prefer to play? Would you rather play through all of Tamriel in TES III or IV? And why would you prefer said game?
Also, do you think the foundations from which these mods were made could be brought together in TES V? Just how big a recreation do you think such a united community could make?
And how quickly do you think they'd jump on it? I've heard that Tamriel Rebuilt started their planning on rebuilding Morrowind for Oblivion years before it even came out.
And how do you think Bethesda would feel about it? Would they more likely be proud or resentful?