Recommendations for Mail/Calender cluster?

Hi all, at the Uni where I work, we currently have a 2 node (2 x v480) Sun Cluster running iPlanet Messaging Server 5.2. We are looking at upgrading the mail system to Sun Java Messaging Server 6.3, and possibly Calender, later this year. What do people recommended we upgrade the hardware too? eg 2 x T2000 to run Mail and Calender? or maybe 2 x T2000 for mail and a T1000 for Calender? etc etc

Any suggestions would be greatly appreciated.

NB: This mail/calender cluster may also serve as an NFS cluster too.

Stewart

[543 byte] By [mcleansa] at [2007-11-27 4:56:11]