+1 for Combi-plan. I bought my tank to be able to do quarter plate; the film holder is adjustable for that, 9x12 cm, and 4x5, and will take sheet film (in curved slots) or plates (in straight ones). I have a weakness for old cameras, so this ability was very attractive (though I haven't used many of these exciting possibilities yet). I have come near to breaking the tank on a few occasions though. For roll film I use stainless tanks, and if I could replicate the Combi-plan in steel, I'd be a happy bunny.