For MF I generlly use a couple of Fuji rangefinders. But they don't focus that close for some of my "studio" shots. And like I said in my previous post, if I am just playing around with some unresolved ideas, running roll film through the 6x7 roll film back is much less expensive that using 4x5 film for experimentation. With 100 iso film, I can still get some excellent prints this way.
To me, it's the best of both worlds.