My copy of "BioWare - Stories and Secrets from 25 Years of Game Development" arrived today, and the first section I went to was the making of KotOR (Naturally), and I was surprised to see a page about Sleheyron, including the internal design notes for the planet. Not sure if this is going to be help to anyone, or even this is already known, but still... nice to see something new about the planet.
PS. Sorry for the pictures, No scanner atm, and had to go with my phone.