I have published a technical report that discusses the implementation of our vertex connection and merging algorithm:
Implementing Vertex Connection and Merging
http://www.iliyan.com/publications/ImplementingVCM
The focus is on the efficient path MIS evaluation. Special cases are discussed, such as correctly handling infinite lights and orthographic cameras, as well as point lights and specular materials. There's also a discussion on how to apply the weight scheme to bidirectional photon mapping and bidirectional path tracing. In the latter case, the scheme reduces to something almost equivalent to Dietger's. The slight differences are because the scheme was independently derived (but I obviously couldn't publish it before the VCM paper).
SmallVCM has also seen an update with more comments as well as references to the specific equations in the tech report, with the hope to make both the implementation and the tech report easier to parse. There have also been discussions here lately on the eye connection technique and the associated pdfs, so interested people might want to check out this part of code, which has been refactored and more heavily commented.
