Wow, you can now get your hands on a non-commercial version of Renderman for FREE. Pixar has been selling Renderman for a long time. That said the asking price of £1200 was pretty damn reasonable for such an amazing piece of software. Nowhere near as good as FREE though.
Problem is now a question of if your fave 3D application is supported and integrated. Blender isn’t at the moment so no dice there unfortunately.