Why not just convert http://www.tesnexus.com/downloads/file.php?id=23018 to work with Morrowind?
Because the map used in oblivion is a completely different scale and scewed dimensions.
Good idea, in theory, but......
Either the project is going to give you a tiny "sample" of each province, it's going to take the ENTIRE modding community several years even if everyone agrees to tackle it, or it's going to end up as a bunch of big empty areas with nothing worthwhile seeing. The Tamriel Rebuilt Project is already taking several years just to do a decent job on the rest of Morrowind, so multiply that by the number of provinces and you begin to get an idea of the sheer scale and scope of the task.
I'd love to see a "correct" Imperial Province of Cyrodiil, as well as Black Marsh, Elsweyr, and whatever else, but it'll never happen. The old Morrowind game engine won't support that large of an area, and it would be a bad idea of a joke, in my opinion, to make "mini" provinces that are less than half the size of Vvardenfell, just so they all fit. The best we can hope for is that Bethesda will get its act together and produce a decent TES V that has the same kind of long-term appeal as MW and is able to handle a much larger map size.
My suggestion is, if you've got the talent and time to do that kind of work, contact the Tamriel Rebuilt team and lend a hand there. The remainder of Morrowind is probably going to be about as much as we're likely to see in any sort of "reasonable" form.
Ill have you know the game does support that HUUUGE amount of land, the only thing that stops me from showing you all of it in one whole go, is the memory restrictions of MGE when creating distant land
Also, I did offer my hand at Tamriel rebuilt, but i didn't feel welcome