Daniel, do not have one of these..but do have one like it from Dan Pelland (APUG member). Was looking at these on ebay, when Dan joined and I ended up going with his. Others here can give you their thoughts on other makes, but I am very happy with Dan's. Try and PM him to see what he might charge for a 9x18.
One other thing, the best advice I have been given at these size is to go with a vacuum easel, rather than pressure type.
Yes I have one of these contact printing frames. I bought an 8x10 to make 8x10 contacts. The quality is vert nice but I do have one complaint. The frame puts a white boarder around the print. At first I liked the white but now I don't. I find it hard (impossible really) to keep the boarder even around the print. I could have solved this by purchasing an 11x14 frame to do my 8x10's in the middle.
Overall I like the workmanship but don't use the frame much because I find the white boarder annoying.