Photo Book Size Question

I'm trying to make a photo book for my Portfolio, thus i need this to be a 11” x 8.5” book. I clicked on your Layflat Imagewrap Hardcover which had everything i needed/wanted, but when i went to the "buy now" part the 11” x 8.5” was not available. the biggest it showed for the layflat was a 7" x 5". Why is this? am i missing something? This is a time sensitive matter so any help would be appreciated.