Oy, there is something wrong as I have not been receiving email updates about this thread. My apologies to everyone.
So an update on the current status:
A BIP describing the authenticated prefix tree resulting from my research has been published to the developer mailing list, and is available for view
online. The feedback I got from that is being worked into a 2nd version of the proposal which is nearing completion (I'm currently adding descriptions of the peer-to-peer messages and JSON-RPC APIs, then it is finished).
I also have about 80% written of a BIP describing the validation index, the outline of one describing the wallet index, and an assortment of notes towards two future BIPs related to document timestamping and merged mining improvements. These are the first deliverables, as once developer consensus is achieved other people can start working on implementations of these various features.
Besides the python implementation hosted on Github, there's a C++ implementation suitable for inclusion in the reference client that is about half finished. It could use a lot more unit tests.
However since funding mostly dried up after Armory's very generous donation some months back, I have been working on this proposal only part time (1-2 days per week). The rest of my time is spent on various other funded projects including CoinJoin and preparation for blockchain pruning. Work has
not stopped, just slowed down.
@dansmith, unfortunately I think there's some confusion. I did not switch addresses between the first and the second funding rounds, so most of the money received at that address was for the first round. (And, while it sounds like a lot, bitcoin was worth an order of magnitude less back then and it was mostly cashed out upon receipt. Too bad I don't have a knack for predicting markets :\ ) I was unable to finish out the round, so I've been forced to take on other (thankfully related) work as well which has unfortunately slowed things down.