You really need to hold these cameras in your hands. You can't really go by the way they look.
I have owned all three of the Pentax 645 film cameras (645, 645N and 645Nll). A very good friend of mine owns the Pentax 67 with the wooden grip. Yes, the 645 cameras are bulky compared to small 35mm cameras but they are no where near as big, heavy and bulky as the Pentax 67. I used to own a Mamiya RZ67 with the flash grip. I would rather hand hold it using the waist level finder then to hand hold a Pentax 67 with pentaprism finder. Throw the metered prism finder onto the RZ and I might rather hand hold the Pentax 67.
I own a Hasselblad 500cm with 80mm lens. It's light and a joy to hand hold (at least for me). I mostly use the waist level finder. If the Hassy is beyond your budget then you might look at the Bronica SQ series. Bronica lenses are also very sharp!
Just something more to consider.