(L) [2006/05/21] [fpsunflower] [UNC research] Wayback!The razor paper has a nice index of concurrent work. I don't think these have been posted yet.
[LINK http://gamma.cs.unc.edu/RAY/] (tracing lod models)
[LINK http://gamma.cs.unc.edu/BVH/] (dynamic bvh, similar to Wald's method)