There are several pure browser iroh custom transport implementations that use webrtc. The challenge would be to have this also work with native clients, preferably without blowing up the binary so much that we can no longer ship it to resource constrained devices.

I won't like - webrtc will probably never graduate to a built-in transport. But we would be very happy about a bare metal webrtc transport and link it from our official docs for people that need it.