Mark why using a commercial party like twillio? There are a lot of good other solutions available. I currently have setup a dedicated server with rocket.chat. The videochat solution they have implemented is using https://jitsi.org which is a complete free opensource video conferencing platform.
With rocket.chat you don't have to install the jitsi on your own server because it is hosted by rocket.chat itself (like cometchat does..). So mooSocial can decide to do that and come with an hosting plan (or raise the plugin price with the hosting included), or let the user choose to host the jitsi on their own server (and provide an installation package as you now do with mooChat > nodejs server)
I think i should go with cometchat at least for now, they have group chat, real time translation, credit integration, mobile app many other features for $199/m
If you don't want to pay fee for turn server, we can help you setup a turn server at your own server. But you need to increase bandwidth for your server.
ketkew if you use jitsi.org, you also need to setup the turn server at your own server.