From what I understand (taking last nights info plus what was said before), housing is going to work similar to LotRO except we will actually build the houses rather then them being already built (and have a functioning yard). Basically instanced housing communities in specific housing zones like the 3 originally mentioned. Certain plots of land will yield the option to make bigger houses, bigger yards etc but you pay more to get them.

As for more then 1 house, this is where having alts might end up becoming useful, what if you could give 'key rights' to your alts and inevitably you could have a plot of land at every zone!