Plans for a 8x10 or ULF are not really existent. But you could buy a wood 8x10 in some dubious state of repair and ask him to restore it or convert it to 7x17 0r 8x20. Since he would have the existing 8x10 back to use as an example, he could build the ULF back if you furnished the bellows and filmholder(s). Restoration work on the front, a couple of lensboards and you're all set.