I don't think you could do oblivion for WC, for a few uncomfortable reasons
The first, war3 simply can't handle that kind of detail, even if you could find some1 (or some way) to get every single highly defined unit model (even if you scale down the detail, still a hell of a feat)
The second, oblivion as a game was kinda "Ok", mostly great for it's high detail an awesome RPG features, as an online game for WCIII, it wouldn't be as good (maybe not awful, but worse)
The third, if you got all of these resources, time, skills, everything together and created this map (which is a ridiculous f*cking amount), there is still WoW, which is where alot of ppl who got bored of regular warcraft moved on to
My suggestion, make a normal wcIII rpg map, base it off of oblivion, and add alot of really cool (but do-able!!!) special features. The guilds would be pretty cool, and the quests could be fun with appropriately balanced items and stats
EDIT
I didn't read that you already got a high res map together, well if the systems don't lag, GO FOR IT!!!
I'd be interested in seeing the outcome of this