Steve,
It took us a couple weeks to iron it out. We also use this for the management of core platforms and projects to ensure consumers are not dropping items into the product backlog.
We are a Linux shop and use Google Apps for our email. We currently leverage the mail gem for ruby to process the email request. I would expect the same gem could be used in a windows/exchange environment
https://github.com/mikel/mailIn our particular case we usually correspond with the requestor and update the US as necessary. So, we don't have anything that appends or creates a defect, but I am sure that could be sorted out if needed. Appending would likely be a bit more difficult to handle than a defect.
Thanks,
Dave