My most recent acquisition has been a 6x18 pinhole from Zero Image. This camera has the options of shooting 6x4.5, 6x6, 6x7, 6x9, 6x12 or 6x18. I've got a lot to learn in terms of pre-visualizing my scene, but I like the possibilities this will offer. My biggest surprise from this was the field of view was much deeper than I had originally anticipated. In other words, distances showing up on the final image are much further away than when actually viewing the scene.
My first outing used Fuji Acros 100 with a red #25 filter, and was shot in 6x12 format. It was actually far too wide for what I needed. 6x7 or 6x9 would have been a much better option. Here it is in action:
And here are the images that came out of this first session: