I was modeling a building for a friend's ROBLOX game's skybox, and in my opinion, it's a cut above most ROBLOX models. I deleted all upper and backwards facing faces as well as unifying the overly complicated faces. The texturing was done using the texture bake feature within Blender Cycles. Take in mind that this model is JUST for background use. The textures are low resolution, and any angle other than from the front and slightly upward will look like crap. That being said, feel free to use this model in any of your projects, but please do give credit and link me to your production. I would love to see what kind of things it's put into.
I set the model up with an array modifier, so you should be able to easily change the height to any you like, from a single story to several hundred.
If you want to use this model in Cycles, you'll have to modify the materials yourself. Though, you won't have to do a lot, seeing as the textures themselves are set up for easy use.