I have a DICE Video Cradle which has a 1/8" jack like the "old" composite video cable, as well as a pass-thru dock connector. I cannot confirm, but I assume the composite video, right & left audio signals are split off the pass-thru dock connector and out to the mini jack.
I just tried an iPhone w/ V1.1.1 connected in the cradle, and a camcorder cable (just like the old composite cables, but with different color coding on the RCA jacks).... no video out...
The iPhone must be looking for some signal on the accessory pin, or some type of load on one or more other pins to tell it that it is connected to a video cable and thus could send video out.
Unfortunately, this still does not confirm if composite video is on Pin 8, but probably determines that there is some other magic pin setting required to tell the iPhone that it should send video out....
What I'd give for a breakout cable right now
(on a side note, the DICE car interface module, seems to behave different with V1.1 SW than I think it did with a friends V1.02 SW) - when connected to the DICE unit and playing audio the iPod screen switches to a "Accessory Connected" screen and you lose the ability to see the track detail (and the cover art) on the screen - a real bummer when you have a radio head-end that won't display track text.... Hopefully this and more will all be sorted out in due time...)