Where is the Remailer discussion?

Folks- I noticed very little discussion on remailers here. Can anyone tell me of a mailing list more suitable for remailer discussion? In the meantime, maybe someone can answer this: I'm reading the design docs for MixMinion. The authors are saying that reply blocks must be single use because traffic analysis can be done via flooding replay attacks, and that the replay block can be derived from this. I can see how this is the case with simple reply blocks, but what about the reply blocks that have branching and varying probabilities? Couldn't one create a reusable reply block complex enough to foil this type of analysis?