I hereby claim part of this bounty for my work on bitprivacy.

It is MIT licensed, and furthers the goal of making improved transaction privacy a practical reality for Bitcoin users. It might help if you clarify whether funds can be paid for work done before the setting up of this bounty. I'm assuming solutions don't need to be called coinjoin, if this isn't the case you should say.

It's great to see so many people contribute to this bounty.

If you want to help bitprivacy directly, you could try it out and post in the thread.