Whidbey supports a new channel for Remoting – IPC.
IPC channels are for intra-machine communication only and use named pipes. The good thing is, that IPC channels are locked down, so they permit only connections from the local host – and even better, you can ACL the channel, to specify who is allowed to connect.
One scenario that can be elegantly solved with this, is if you want to factor out highly privileged code from your least privilege server process, you can put that code in a remoting server (e.g. packaged as a NT service with elevated privileges), and let your server process communicate with the out-of-proc remoting server. Only local connections are possible, and you can ACL the remoting server to accept only connections from your least priv component.
I normally use Enterprise Services to achieve the same thing – this approach could be easier. at least an alternative.