multiplexing different hosts on a single SSL connections

Hi,
I remember reading some ideas about how to enable that on the spdy group.
Obviously there are different security and privacy considerations for doing that, but there are some performance benefits, especially for proxies/intermediate.

I am not sure it is in the scope of HTTP/2.0 and if this mailing list the right place to discuss this?
Is it covered/discussed as part of some other effort?

- Ido