I have 3-way multiplayer BananaBread working now. Really it's n-way multiplayer, but since I only have 3 computers handy I'll avoid making outrageous claims. My desktop machine has 3 monitors, and you can see the other two players as I make them jump (one on my thinkpad, the other on my macbook). It's late and I have a sore throat, so the voice commentary is lame.
Most of the WebRTC code lives in a library here: github.com/js-platform/p2p. I'm currently working on adding Chrome support and packing the library up for release with some documentation (not much, since the API is very straightforward) and tests.