Back in the mid 90's there was a fellow named Jones that made circular brackets that allowed you to mount the bracket on a tripod and rotate from horizontal to vertical by loosening a knob on the front of it without any other movements of the tripod. I had one of those for the Pentax 6x7 and sold it to someone thinking they'd always be around. I used them exclusively in studio and weddings.They do still make them for 35mm but I don't know about the 6x7. If you had a flash mounted on top of the bracket you could rotate the camera without the flash moving.
Anyone know from whence I speak or have had/seen them? This is their 35mm bracket.
J-35
Anyone know from whence I speak or have had/seen them? This is their 35mm bracket.
J-35