Program to sell vanity email accounts from my domains

I have a couple of domains that would make great vanity email addresses.

Does anyone know of any programs that would let me sell/rent email accounts on my domains?

Here are the ones I have found:

Socket**Mail: Seems like no good reviews
Fire*Ball*Mail: Site looks like it has never been updated
email-prov**ider.org: Want $350 set-up plus ongoing monthly fees FROM ME that are more than I was going to charge my customers.

Any ideas?