All I can say is 'Thanks!' I've been looking for an email server like this for a long time. I can't believe how many of the things I wanted, you have included or are working on.
I'll be looking for ways to help on this project!
We specialize in Flash interfaces, particularly using Flash Remoting/OpenAMF/Java App Server(tomcat)/MySQL/FedoraCore4. We're also getting into Flash Comm Server and media streams (hosting, live and recorded) for video conferencing and messaging - also using Flash interfaces with remoting for data connectivity.
Anything we should put some thought into for you?