Lord of Souls - relevant lore

[Deeza]

Yeah, I'll keep a look out too. It's a big thing we need to get right.

I believe that when someone gets around to posting the descriptions of the Dunmer colony in Solstheim we may get some more information.

Also, the pre-release material hints that there is a major Dunmer refugee population (or descendents of refugees) in Windhelm city, so presumably the dialogue there would be the first place in-game to look for information (plus a 4th Edition PGE if there is one)

Also:

Something else I found out: as of the timeline of Lord of Souls, Great House Indoril still exists. Given that it was by far the weakest of the Great Houses, that strongly suggests that the others do too.

There are, however, now a fair number of Dunmer who do not associate with any Great House. But perhaps this was always the case?