I've recently been in a situation where an Exchange email server went down and we weren't able to bring it back online after 48hrs, so some incoming emails bounced. Also, users weren't able to send or receive emails for a few days, which was a sore point and caused some early withdrawl symptoms.
In a post-mortum someone came up with the idea of setting up a quick and dirty webmail server to catch those emails during the outage so that at the very least people could receive and send emails. I've never done this, but it sounds like a good idea. Has anyone tried something like this before successfully?