I have a club with extra prims above it. I can have 3 200 prim skyboxes and I'm renting this out for 350/week. It's build your own but I really have no limits as to what you can do as long as you stay within the plot of land.
IM Addison Janic if you're interested in a skybox. I can only put up 3 so they'll go fast, make sure you claim yours!!