While working on a new book cover for a client, I discovered that CreateSpace has finally relaxed the rules about the placement of the barcode on the back cover of their print books. Previously, a blank space had to be left in the lower right-hand corner (as evidenced on their templates) into which CreateSpace added the barcode during pre-production. Designers were not left with the option to place the barcode anywhere else.
Now, CreateSpace allows the placement of the ISBN/price barcode to be anywhere on the back cover, so long as the barcode still fits within a 2″ x 1.2″ white box. (Personally, I find CS barcodes unattractively large, but I digress.) You have the option simply to leave a blank white 2″ x 12″ box into which CreateSpace will add the barcode, or to add your own. You may also add a QR code but it must be in addition to, not as a substitute for, the ISBN and price barcode.
As for the price code, CreateSpace will also now allow you to put in a designated price instead of the standard 90000 (no MRSP) code, but I still advise against this: if you change the price you have to update your file, and the same file is being used in both the U.S. and Europe. If you sign up for Expanded Distribution, the same file is also going to third parties for distribution in other countries.
CreateSpace has created a PDF Submission Specification document that can be downloaded here (this is a copy of their direct link). Or go to their website and scroll down to the bottom of the page to find the link.