Freelancer:
adot8702
Squirrel Mail
You can find perfect solution here for your each and every requirement as described by you. A powerful Junk Email Filter is also there for you. A lot of plugins are there for use. you can create your also as according to your need. It is very famous service that you can see in "The Social Network". SquirrelMail was spotted in use by Mark Zuckerberg's and Sean Parker's characters. So far, no one has contacted us regarding our cut of the box office. ;-)