More than just DIY, this is better than many off the shelf solutions... if for nothing else than a decent matte IPS screen. Not to mention you have more control of how to get pictures to the device or turning it on/off however you want, I for one would add auto on/off via a motion sensor.

This also presumes you’ve hacked the machines on the network that also typically have a firewall... not to mention an antivirus that will catch the vast majority of keyloggers. I still think you’ve blown this risk out of proportion. If you have a high risk for being targeted it might be a valid concern, but even then…

The SSL is still terminated at your computer not your router, so it would still be encrypted traffic. I don’t think this is quite the risk you’re suggesting it is.