Coming back after a while.
I realized that whatever sort of 6x12 one takes (maybe with exemption of Polaroid conversions) - all these cameras are intended to be used on tripod. The largest film area with decent RF is probably the GW690 (which I may get if me and my wife will start to think seriously about a long trip).
So considering the 6x12 I would say that what would make sense are cameras like Technorama, Horseman 612 (or the cheaper ones like DAYI, footman, etc..) or similar - which when coupled with 1 or 2 lenses are reasonably compact and fast to use.
One more question:
I have recently come across a 6x12 camera(s) that are built around Mamiya 6x7 back (modified to take 6x12 images). Does anybody have experience with such camera / back? These seem to be quite rare and often custom built. Was there ever a 'standard' Mamiya 6x12 camera?
What caught my attention was the compact size of the camera - seemed much less bulky than those 'standard' 6x12 cameras (like mentioned above)