Just for everyone's awareness, these are now available from Costco, and for a significantly lower price than Tire-rack. I called to place an order yesterday, and the sizes I bought were readily available and in-stock; they should be arriving within a week. They are not orderable online yet thru Costco's websites, but any tire center tech can look them up BY NAME in the system to order them for you in person or over the phone. Have them search specifically BY NAME, as they currently WILL NOT SHOW UP if the tech searches by size.
Have them reference item #1146866 (PS4S in 255/35R19) or item #1146910 (PS4S in 275/35R19) if they need to see an example of the exact name/nomenclature to search by. Big thanks for M3_socal for thease item numbers!
See the first two pages of this thread for more details on how to purchase via Costco:
http://www.m3post.com/forums/showthread.php?t=1361434