Westinghouse has a history of launching behind schedule, especially with their largest products. In the case of the 52 they are also constrained by short supply of the panel in question, just like the LVM-47w1 was last year when it launched.
Speaking of pre-orders for the 47" I emailed JR.com about how long their pricing on the 47" would hold, but they haven't gotten back to me. I can't personally pull the trigger until either cnet or audioholics tests one and verifies good greyscale tracking, color accuracy, and some details about functionality.
One would think they'd have the product up on their website by now too, but no such luck.