I think I'll pick this up, it sounds like it deals with some stuff I've thought a fair amount about.

I've had some specific thoughts on a semi-anonymous system that splits the difference between concealing identity and allowing identity verification, originally conceived of as a distributed banking system to minimize trust requirements, but fundamentally a reputational system. The required crypto to make it work is currently marked "Magic Occurs Here", but it navigates enough of the pitfalls mentioned here that what I have might be worth putting up to scrutiny.

In case other people here are interested in hearing about this idea, the general idea is an account-network where some group you're a member of (i.e. your college, your church, LessWrong, a warez forum) can grant you an account, but can't check their membership roster without your explicit consent, and other members of the same group can verify shared membership without learning what account you're associated with or involving the group itself. I've worked out some basic specs for what's needed, it shouldn't be too much work to get it to at least the level of a Discussion post.