Most of those shaders written back then are pretty much worthless now that Renderman has introduced RIS mode (instead of REYES mode), which was introduced last year. Pixar recommends writing shaders in C++ now instead of in RSL, as C++ shaders are just way more performant right now. OSL is pretty mature, I know that both Sony Pictures Imageworks and Double Negative use it in production. Now that Renderman also support OSL I'm pretty sure we're going to see OSL examples posted online. OSL shaders are awesome compared to RSL shaders, as OSL gives all control to the renderer, which allows it to do a lot of optimization (such as using the renderers own importance sampling strategies).