No idea what price Sony will come in at, but remember ~$100 of the Xbox One price is the Kinect. Sony's machine is specced a little higher but also a bit more off-the-shelf. I think $429 is possible.
Kinect 2 has twin 1080p cameras, but if I had to guess I would have imagined the PS Eye light bar, 8GB GDDR5 and added CPU power will more than make up for that. I do believe there was speculation that the PS Eye wouldn't be standard though, so maybe.
Barrier of entry on the high-end boxes seems intentionally high to gouge enthusiastic early adopters IMO. Sony weren't sufficiently punished for 599, they came out of things just as well at this point in the generation as Microsoft... what incentive is there to make these boxes affordable?
I do predict Sony will enjoy making a point of how 'free' things are on their platform though. The non-social things anyway.
I'm out until next year definitely. I'll just have to play catch up.