Sock Architecture is now available for purchase! $16.95 for the PDF version, $26.95 for the PDF and printed book, together. Printed books should start to ship in a few short weeks.
I'm told that the link above might not work forever (there is some behind-the-scene streamlining happening on the site). So, if it doesn't work, try just http://cooperativepress.com/.
I hope you love it!