WordPress MU

Hi guys,

I'm looking to do the following:

* WPMU (and BuddyPress) installation at "example.com", with Domain Mapping installed
* A user sets up a custom domain, "custom.com"
* Emails can be sent to email addresses at "custom.com", received by the WPMU installation at "example.com" (an MX record pointing to "example.com"?) and then an email sent to the previous address provided by the user when they signed up "me@gmail.com"
* This means that emails sent to a specific address at the custom one "hello@custom.com" will be delivered to "me@gmail.com"

WPMU must have the ability to receive emails (post by email), so could it intercept these emails and send a copy of them to the users private email address? Later on, I could create private messages in BP from the received email.

"received by the WPMU installation at "example.com" (an MX record pointing to "example.com"?) and then an email sent to the previous address provided by the user when they signed up "me@gmail.com""

It's email. MU isn't involved at all at that point. Having the MX record handles it. Then you set up a mail forwarder to go to the original address.