mailparser will (hopefully someday) be a Python library that reliably parses 99.9% of mails and provides an easy access to contained information ranging from simple header fields, body parts and attachments to extracting Outlook TNEF, Delivery Status Notifications and other exotic stuff.
You may have used it and it may be a bit difficult, but it kinda worked for your text email. Sadly, email comes in many forms and some of them are not recognized by Python's email module.
Don't know yet. This project will take all tests from mikel's Mail and probably also some code. Mail uses an own grammar and it looks like this project might have to go the same way.
The API will be easier than Python's email module (not that hard).
At this point I do not plan to include mail construction, but only mail parsing.