It'd be cool to have a video chat function a bit like Skype, but encrypted and safe.
I think the best way would be through TLS and S/RTP. Lync/Skype for Business uses a similar method for voice and video sessions.
The certificate could be exchanged through your symetric key.
Well,I don't have any money but this is something people would pay for even if the frame rate isn't very good at first.
Well I think starting with "recorded" videos would be a great start. And getting "live" video would ba a second step.