First Draft so I don't forget the process for the future.

This is the process used to import a csv that was sent to a gmail address using feeds and mailhandler. Everything is on Drupal 7

This is a rough approximation of what I did. Some things need some polishing e.g. I set it up to import even if it isn't authorized on the file import. I need to secure that.

Install PHP IMAP library (On your server)
First install Mailhandler
Install Feeds
Install Attachment Links

Create the Gmail account you will be importing from.
Enable POP in Gmail ( I Also set it to archive messages once they were downloaded to prevent multiple imports.

Enable the modules you installed on the site.
Create the content type you are trying to import.
Create a file holder content type to hold the csv you are importing from. On the content type edit page there is a new vertical tab for attachment links, enable it for the file field. I set it hold one fiel and used the file widget.

Structure > Mailhandler Mailboxes
+ Add
There is a bug currenlty when it tries to use ajax to test the settings. Fill out the domain and password last, you may have to save it and come back in a couple times. Before clicking save always click elsewhere on the page to initiate the ajax call and wait for it to complete or it won't save the settings.
For Gmail use pop as the protocol