Progressive Photon Mapping is a new algorithm for unbiased raytracing. Recently, I implemented it in tlrcam. Since I am transfering universities to carnegie mellon, my website at brandeis is down. Currently, you can look at the work at:
I am currently developing new techniques to make this algorithm even faster, so check for updates if you are interested!
The first picture was rendered in half an hour.
http://graphics.ucsd.edu/~henrik/papers/progressive_photon_mapping/
http://www.andrew.cmu.edu/user/mmirman/
http://tlrcam.blogspot.com