You are saying about SmarterMail and MailEnable, but prefer Linux. If I am correctly, they are mail servers running on Windows only.

anyway, we will have new DA with NeoMail and SquirrelMail next week. Are you interested? I can offer you our RC1 package with 2GB space and 30GB transfer at $15/month

Let me know if you have any question about our services.
thanks