A bunch of us are thinking of creating a prototype of
Colored Bitcoins (AKA Mastercoin/Twitcoin). The TL;DR is using the Bitcoin blockchain to represent several different coins, each with its own color.
The color is defined and calculated by the client: I can release a ripper234client that designates a certain address as a "color source", and every transaction originating from this address becomes colored. This client then displays the number of ripper234coins you have.
This thread is not a technical design thread, but rather a question - out of the existing full clients out there, which would be the easiest to fork for the purpose of this experiment? I would have preferred a client based on bitcoinj (Java > C++), but I believe there isn't a real (GUI & batteries included) client written in Java, right?
So out of the known alternatives, which would be the easiest to work with, most documented, has the best organization into modules ... ?