Thought the Eurogamer interview was interesting. Talking about a clip-on thing for the dualshock with lights that could be detected by the PS eye...for a while Sony filed a fair number of patents relating to light patterns on a dualshock as picked up by a camera, for tracking position/orientation. The sixaxis/dualshock already has 4 little leds on the front, but these patents also proposed different led layouts that might have been more useful...and I guess this is where a clip-on might have entered the equation.
Anyway, as it turns out they decided to make something more specific (Arc), but interesting nonetheless.
Also worth noting his comment about future projects - I dunno where people got the idea Sony had signed them to a multi-title deal, but the interview confirms that this wasn't the case. Maybe Sony will be their next publisher, maybe not...I guess a lot may depend on HR's performance. Whoever they sign with, though, I hope they get the time/resources/patience they need to make the type of games they want to make.