I've been sitting on the idea for a while but hadn't really thought it through enough to make it workable and didn't have the time to try. For a description, I'll put a detailed description in spoiler tags as it has major Morrowind spoilers, and I'll put a shorter one below if you do not want the main storyline and some side ones spoiled for you.
The Short
An epidemic level outbreak of corprus disease will provide for a zombie-outbreak type scenario if it is severe enough, while still allowing for a possible stop to its spread and providing clear (if seemingly impossible) goals for the characters. Set several years before Emperor Uriel's assassination and the would-be Oblivion Crisis, characters from all corners of Tamriel will need to come together at the Imperial City and travel to the dangerous, fallen island of Vvardenfell in Morrowind in hopes of stopping the greatest threat to Tamriel in an Age. Not only must they survive against this outbreak long enough to find a way to end it, they must also contend with the demigod of Red Mountain, Dagoth Ur, who is devoting all of his resources towards conquering this weakened Empire with the ever-growing corprus horde under his control in addition to his own House rallying behind him.
This RP has potential for a lot of travel, combat, and whatever character and story development we RPers may wish to add, but it will not feature safe areas to rest and recuperate once they leave Imperial-controlled territory. This is mainly a survival RP, as characters do not necessarily need to be in the questing group but may also be survivors encountered along the way or different factions seeking to further their own agendas in Morrowind. It also allows for more powerful characters than normal, as surely the best and brightest have some among their ranks who wish to get their hands dirty in putting an end to this.
The Long
What is known without spoilers:
Dagoth Ur is the major antagonist in TES III: Morrowind (or at least there is no storyline to support them) and, from his lair under Red Mountain. He is known to have created the Blight, a terrible disease spread by ash storms, diseased creatures, and curses. Even worse than this, however, is a variant or related disease known as corprus disease. This disease, extremely contagious and with no known cure (attempts from some of the most powerful beings in the area have failed to find a cure), disfigures the victim as well as driving them to insanity. Essentially they become feral and physically stronger than they had been. Here are some images to show a few of the effects: http://images.uesp.net/a/a8/MW-creature-Lame_Corprus.jpg, http://images.uesp.net/7/75/MW-creature-Corprus_Stalker.jpg.
Spoiler-including explanation:
So what happens if the Nerevarine failed in his/her quest to stop Dagoth Ur? What if, in the final confrontation between the two, Dagoth emerged victorious and with all of Kagrenac's tools? That is the premise for this RP, an alternate course of events after the story of TES III. With the tools at his command and the Nerevarine defeated or converted, Dagoth is able to safely bide his time and continue strengthening his forces while significantly decreasing the Tribunal's power. Eventually, they will cease to be equal to him in power and the Ghostfence will fail as they lose the strength to maintain it. From here, the Blight and corprus will spread like wildfire, across Morrowind and beyond. Morrowind would be conquered by Dagoth; there is no other way to word it. Those who did not die or succumb to corprus while fighting would be forced out of this land into either Cyrodiil, Black Marsh, or Skyrim. However, it would not stop there. Corprus would spread as an epidemic, unstoppable as it was and not hindered by the Ghostfence. Soon the Empire at large would be fighting this outbreak.
At the same time, it is not simply some disease outbreak or zombie apocalypse: Dagoth Ur still has other means of furthering his goals and he still remains as a force that needs to be stopped. This RP will be composed of either survivors of "fallen" provinces or those coming from other provinces to try to stem the tide by venturing behind the Sixth House (Dagoth Ur's fallen Great House) line of advance, back into the inhospitable Morrowind, for two objectives. Their first is to investigate a lead provided by veteran Blade Caius Cosades into a possible cure for the corprus disease. Their second is to work together to make their way into Red Mountain, recover Kagrenac's tools, and somehow put an end to Dagoth Ur's dreams of an empire. They don't have the benefit of Vivec or Sotha Sil for wisdom on how to use the tools, and must learn this on their own as well.
So, if anyone is interested, or has questions, comments, or suggestions to add, this is the place to do it. I am confident in the potential of this RP, though I haven't been active again on the Elder Scrolls forums long enough to see if you guys have done something like it recently. And yes, I won't lie, my desire to do this is partially inspired by having watched AMC's The Walking Dead. That doesn't mean that I'll be taking ideas from it as I have some confidence in my creativity It was just one of several motivating factors.