To be honest the buildings on the front would be rather hard. The front one may be doable, but the background ones, not so much. I am working on one that is about 8 inches wide 16 inches long, and 24 inches tall. Looks fat. To get that slim look, and still look like your guys can move around inside it would be huge.
As far as other Tau scenery goes, I put this together for Iron Chef 4
http://www.librarium-online.com/foru...u-outpost.html
And hope to have another piece up within a couple weeks for Iron Chef 6.
The key is round. Round all vertical corners, and most horizontal ones. Insulation foam works well, cause it can be sanded, but sucks up paint. The paper plates I used in that last one work well for round structures, but are kinda limited because of thier size. I have used bottle for small round sturctures, but they have to large a radius to do just building corners. Pipes, tubes are pry a better bet for corners.
For added bits, use plenty of attenaes, some drones, lines along edges like the outside of drones(inset if you can, painted if not)
Hope this helps, I will try of think of anything else and either put in my IC6 or put here.