Fotoman is offering a 6x24cm camera.
Canham makes a 6x17 back for 5x7" cameras.
The 6x17 backs for 4x5" cameras are handy things and are very affordable. Unless you're planning to shoot a LOT of 6x17, a 4x5" camera with a 6x17 back is a much more versatile tool. Even if you don't want to deal with sheet film, you could add a more conventional sized rollfilm back and have a great camera for landscapes, portraits and architecture, and you can learn to use its features as you need them.