My concepts for Sleheyron are those originally planned for Knights of the Old Republic. I know Sleheyron is dull and brown, but it's a world in Hutt Space, and as far as we know, Hutts have bad taste in architecture. Most of the brownness would be a result of the sky lighting (this judging from the footage of the cut Sleheyron content). Just imagine what it will look like after the Forceless Collective takes over this planet. As for other buildings, I don't think Sleheyron would have as good city development as say, Coruscant or Nar Shaddaa (or rather, it used to considering this takes place after the Yuuzhan Vong war). As far as I know, not every planet in Hutt Space was affected by the Vong war. And to think, it would seem that it has become the new Nar Shaddaa. I think Sleheyron is a perfect setting for our first encounter with Forceless Collective; you know, urban setting, redish sky, you get it.