I'm looking at it, but so far I haven't found that mechanism. Some 
interesting sidenodes, though:

- Apple's rcd.app seems to widely use AppleScript to communicate with 
the apps supported by default

- Front Row uses Core Image and OpenGL a lot internally.

- Front Row uses AppleScript to communicate with iTunes and probably 
other applications

- Front Row does not seem to be truely extendable by third parties at 
this stage, since it seems to contain everything that makes it up in 
one binary, not in seperate Cocoa bundles or the like.

I'll keep an eye on the topic nonetheless.

Felix