Why is it that you need 6x7? I would say that if walking around is your main use for the camera, and you need something with a low price tag, a 6x4.5 or 6x6 camera would serve you best. A Bronica SQ, for example (Hassy clone), or Pentax, Mamiya, or Bronica 645s.
I have two Mamiya Press bodies (one Universal and one Super 23), and they are more obtrusive than a waist level RB/RZ, though they are great cameras. They are also not small or light.
The Fuji Rfs are cool, though not the choice if you want a system camera.
If you need 6x7, I would think about a Pentax 67 and a WLF. They are simple to use. It is basically a big 35, with all the drawbacks and advantages of such. Its main benefits on the street are the D of F scales, the lack of bells and whistles like an RB/RZ, and its shape that lets it hang against your body with the lens oriented forward, unlike the RB/RZ.
Be aware that the Pentax 67 shot from eye level needs the fastest shutter speeds for the sharpest shots. That is why I suggested the WLF.
Also, if flash is a consideration, the Pentax can only synch at '30 or slower, while the RB/RZ can synch at all speeds.
The best of both worlds would be a 2x3 Speed Graphic. They are light, compact, versatile, well made, and inexpensive. 6x6, 6x7, or 6x9 capable, focal plane or leaf shutter, ground glass or viewfinder focusing, etc. No D of F scales, though. You can rig your own, however, or use charts.
