My changes from yesterday are now in svn trunk so you can proceed with the improvements you want to work on. The relevant code is in the mojoPortal.Net project Email.cs.
If you add support for a from address display name to be passed in you should create a new overload.
Currently there are methods named SendEmail which use the DotNetOpenMail library and SendEmailNormal which use the System.Net classes.
Ultimately once everything is working and tested using various encodings I will move the system.net logic into the SendEmail methods and deprecate the SendEmailNormal methods and remove references to DotNetOpenMail.
Once you have completed your enhancements for encodings and display name and they have been tested thoroughly, then I will do the work to add a setting in the WebStore for the email display name and I will also add it as a site setting so it can be used more generally in other site emails.
You can create an svn patch and send it to me when you are finished.
Thanks for your help with this!