I recently released a REST and SocketIO NodeJS framework called Feathers that ties in very nicely with CanJS. Alexis recently made a cool demo at the DallasJS meetup how to use Feathers to turn an existing REST API into a real-time API and then update the CanJS side to use the websocket events: https://github.com/DallasJS/commanders/tree/feathers
I am also working on a CanJS model adapter for Feathers.