I just started playing dark sun, and to find terrain and buildings that work for a village in the middle of the desert, or a desert fort/desert city is pretty impossible. Something like that would be really cool!

It would be nice to have some greater variation, but for the time being you could get by with things like and

The following sets all contain useful material (listed in descending order of relevance):

has a number of buildings and props that woudl work well in a desert village or city, and some desert looking ground tiles
you already know about.
has a wooden fort that will work in desert settings, and props for an oasis.
has tents and trenches suitable for a desert setting (and the siege engines would sit well on the city towers)