IEEE 1394 is the name for the standard, Sony did indeed create their own connector (a four-pin unpowered connector) however that got rolled into one of the early revisions to the spec.
The design was (I think) initially started by Apple but delivered by a working group involving contributions from several other companies as well (including Sony, as it happens).
Personally I'd love to see a revised Cinema display that took advantage of the abilities of Thunderbolt - to have what is effectively a docking station built into the display with audio*, LAN**, maybe an upgraded graphics solution built in to the display. USB and FW too for that matter, IIRC you should be able to tunnel them over the thunderbolt link so long as appropriate hardware is present either side of it.
A one or two cable docking set up (TB and seperate power) would be great from a convenience point of view.
* But please for the love of god have audio out ports on the back of the display - while the current cinema display speakers are way better than any laptop they're nowhere near the standard of the desktop speakers I have on my desk already
** WiFi is great when on the move but I will *always* prefer to use a cabled LAN connection where possible.
I never thought about an updated ACD.. it would be cool to have speaker out.. and ethernet in on it too. And with a single cable to the mac- power everything. That would be really cool.
But whatever.. I'm still hoping for a thunderbolt adaptor for my iPhone and iPad.....