Umut, I've been through f295.org a time or three. I've kicked around the idea of 6x17, but I'd just as soon enjoy one in 4x5 as well. My 120 pinhole isn't quite a full 6x6cm frame (thanks to the quantity of beer I consumed while measuring and cutting), but I like it well enough. Truth be told, I'm not particularly interested in the highest quality pinhole that can be constructed. To me, pinholes are about the imperfections that make them fun and personal. What will probably happen is I'll likely end up building a box camera 4" deep, and I'll likely take the high-E string end from my Stratocaster (.012") when I change the strings and shove it through a piece of brass stock. That should cover a 4x5" negative, yield about a 75 degree angle of view and leave me with about f/340. The results may end up worth printing, or they may end up very much the opposite. Either way it will be fun!