I made a MM mod using Morrowind. I deleted all the stock cities and NPCs and replaced them. I used the buildings from the Imperial cities and forts and the threes but not the giant mushrooms. It was also very easy to change character height. Various races and monsters in the Morrowind- Tribunal and Bloodmoon game became recognizable MM races

Elves = Wood elves Humans = Imperials Dwarves = Wood elves Goblins = Orcs Various other monsters could be adapted fairly eaily to fit a MM world. Granted I couldn't get all the monsters but I could get a lot of them.

I also modified armor and spell files to create approximations of MM spells, armor and weapons.

I called the expansion "Harmondale" and it would run just fine on an XP machine. But it would not run concurrent with a normal Morrowind game so you'd have to have two instalations of Morrowind if you still play that game. Unfortunately my computer died unexpectedly when the cooling system failed. (Water cooling that develops a leak inside the case causes catastrophic failure even of a HD.)

I had the world up though the land masses were different they had the right names. I'd removed the deserts and ash field from the main map and made all mountains, grassland and forest. I had started looking at the system the Morrowind game uses to teleport you to another map (i.e. going to Solstien or the city in Tribunal)The goal was to be able to have separate maps for Harmondale, Erathia, Bracadada Desert, Dejia, Barrowdowns, Celeste, the Pit The land of the Vori, Eofal, Evermon Islands and Avlee. But it might be possible to even add other places and have unified MM6&MM7 map. Each map would have one major settlement and one or two smaller hamlets. I'd also not figured out how to change the game introduction. But, there is a huge Morrowind modding community. I'm sure somebody knows how to do this. Also a it is possible to even create a party with the abilities of NPC's to fight and cast spells which would give you opportunity to have fungable party as you had in MM8

Doing the maps and towns and NPCs would have been easy. Getting quest thought through and all the various scripting would have taken forever.

My basic premise was that after MM8 the various human and elvish kingdoms had been either overrun or so seriously threatened by barbarians and monsters and that they had fallen into a dark age. Travel between the few remaining areas of civilization has become dangerous and it is not known if some of the kingdoms have actually fallen. The 1/2 elf grandson ( amazingly enough named Sergom) of the four rulers of Harmondale now sits on the throne of an independent Harmondale and is seeking adventurers to go searching for lost knowledge and cities. You have volunteered.