Looks like a great camera. I know what you mean about portability though, it's a pain in the ass. It definitely would be nice to have one that takes either 35mm or 120. If I construct one that takes either of those, I'm not looking forward to reciprocity failure, not being able to develop by inspection, not being able to load under a safe light, and having to shoot a whole roll before knowing what you got. But good luck if you find plans and make one!