Morrowind had a multiplayer mod.. Though it did suck..
I just briefly scanned through this but here is the answer to your question... Not sure why no one had mentioned this... Or maybe they did but I missed it...
You should get it for the PC, instead. Oblivion without Francesco's leveled creatures/items mod is like running on a treadmill that's going a bit too fast for you, unless you have a one of a few class builds. It was so bad that I stopped playing because the only way to advance was use of a series of spells to keep me invisible constantly (ie. heal+invisibility,detect creature+invisibility,summon+invisibility), and that was boring.
I don't like playing games on the PC. For me, consoles are there for games, and the PC is there for the internet, and weird and wonderful programs that do strange little things.
Lol I agree with Lenny as far as most games go there are more on consoles, but RPGs need to stay on the PC man. All the 'RPGs' that I have played off of the PC sucked horribly. Anyways Fallout 3 is supposed to be multiplayer much like NVN was. I am a D&D player and I have never found any flaw in Oblivions leveling system in fact it's about as fast as my DM for Fridays games goes. Which is fast enough to get rid of those stupid players who think the game is made completely of psychodrama.
WetWired WHY THE FUCK ARE YOU PICKING FROM THE CLASS LIST?!?!?!! THOSE CLASSES ARE TERRIBLE!!! Everyone knows you should make a custom class, EVERYONE!