Create MailWizz Extension that allows a customer to add a Google account with the one click "Click to Signin" to send mail and have it setup properly with bounce server, sending domain, etc.
It doesn't seem too difficult as there's the ability to add accounts for individual customers, but we need it so they can add their gmail account themselves from the customer section (because right now only admins can add email accounts) and have everything setup so they only need to "click to register".
After we do this, there are several other extensions that we'd like to hire you for also.