I'd be sceptical of using any of the heavy cameras or 'box' cameras like Hasselblad at low shutter speeds hand held. Sure enough the inertia of weight helps, just like it's easier to hand hold a Nikon F steady than a more modern polycarbonate SLR. But is steadiness absolutely repeatable, no it isn't, and considering the number of shots you get on MF means banker shots soon eat into the roll. So if you want to use slow film or don't live under year round sunshine then accept a tripod is going to be needed, or choose a camera that is more amenable to being hand held.
I think the easier to hold cameras with any type of film or daytime conditions are more or less self evident, almost any of the TLR breed, the Fuji 'Texas Leica' range, and folders in general. The Fuji GW GWS rangefinder cameras are hard to beat, they have outstanding lenses, and they are either 6x9 or the rarer 6x7. That said I always use my TLR or Fuji cameras on a tripod a) because I don't live in California, b) what's the point of MF if you don't go for quality, and c) blasting through film isn't practical, so I accept I work slower and can afford to set the camera and tripod up and quietly contemplate the scene before pressing the shutter. And if I had a Pentax 67 I'd most definitely use that on a tripod, it would be a default decision. It's worth remembering what they were most often used for, studio work, often they could be hand held, but either way with a lot of light around. So look out the window and ask yourself if there as much light as a studio flash, no, get the tripod out.
