FYI, I’ve got MMS-Monitor published now. It’s not substantially different than what you’ve already got. For others:
This project is aimed at people using a Gnu/Linux phone and a cell carrier with different APNs for MMS messages versus general internet data. The intent is to allow the phone to be configured for general internet use by default and yet still get an alert when a MMS message is pending. The user would then switch to the MMS APN to receive the message and maybe reply, then switch back to the non-MMS APN.