I am actually working on extending my Google Calendar Search application to include a Gmail notification device option as well as email searching capabilities. This solution will not require a middle man mail server and your hub will work directly with the Google API's to send the email.
I should have a version posted this week. I will tag you once I get it released so you are aware. The Google API setup can be a bit tricky but once setup you shouldn't have to mess with it again.
