(This is a simplistic equation, which does not take into account the practical limitations of there being only so many total messages flowing in the system, a point addressed briefly below. If only 10 messages "enter the system" and 10 messages "leave the system," the attacker has an easier problem than than a D = 3125, for example, might otherwise suggest.)
Since the remailer system works better (harder to track messages) as message traffic increases, then perhaps the remailers should circulate bogus messages around the mix in order to sustain a minimum level of traffic. As more real messages enter the system, the remailers would decrease the number of bogus messages they issue. How would a remailer tell the difference between a real message and a bogus message from another remailer? It wouldn't, but that's ok. All a given remailer cares about is the number of messages coming in versus the number messages that constitute a "good" level of traffic. If a remailer isn't seeing enough traffic, it would issue some bogus messages that would pass through a random set of remailers and eventually come back to itself. If all remailers did this, then I think the system, as a whole, would always have enough messages flowing though it. Real messages would not have to be delayed to defeat traffic analysis, they could be tossed into the mix as soon as they arrived at a remailer. Jim_Miller@suite.com