I've been informed that the 'teardrop cone' woofer was indeed a development prototype. It seems that a calendar year elapsed between that prototype shown at the January 2006 CES press conference, and the actual shipment of the finished 'star-plane' product in early 2007. It seems reasonable that much of that time was consumed by iterating the flat star-plane version of the concept along with its necessary crossover implementation, which would include midrange and possibly tweeter XO changes because the woofer acoustic hole went away. I bet the final XO was simpler.
I presume that the acoustic launch plane of the star plane would be farther forward than the teardrop cone prototype. Time alignment would require a different baffle angle - but the cabinet seems unchanged. There is no analog time delay in the XO (as there was in the CS5.) Much remains mystery to me.