I have what I think is a fantastic idea:
Make it so that optional E-mail sites are available instead of only one. For those who would use the little envelope icon, there would be a small down arrow next to the envelope that would list optional E-mail sites (such as yahoo, hotmail, google mail, etc.). This little down arrow would be similar to the one that appears next to the little house icon where optional "home pages" appear. This would be an excellent addition to Avant for those who have more than one E-mail address. The additional E-mail sites would be entered into the E-mail configuration page similarly to the way additional "home page" sites are entered into the "home page" configuration page.
You could also create these options in a left click category menu to a right click drop down menu that would list the different E-mail sites the user listed in the E-mail configuration page in "AB Options".
I hope that made sense.