I just picked this up on eBay:
It's the 7x17 adapter back for a Canham 8x10 with 1 holder and a focusing hood. It looks pretty darn nice, mint condition. 36-inch bellows draw. I'm looking forward to moving up into ULF. I ordered some 7x17 film (EFKE PL100) from JandC today, too.
The Canham 8x10 is amazing. With this camera I can now shoot: 4x5, 5x7, 4x10, 8x10, 7x17.
If anyone has any 7x17 images in your gallery, please let me know.