By the way- are there 35mm backs for the V system?
I mean, could I, some how, shoot 35mm using a 500 CM - giving me a kind of xpan frame?
Yes, there are, or rather: were 35 mm backs.
They are rather rare, so do not hope to find one one in a hurry.
They are rare because the idea didn't catch on.
Why use 35 mm film and restrict yourself to one strip format when you can crop any strip, horizontal, vertical or at any angle, from the 6x6 frame?
Why rob yourself of the opportunity to have both a nice square shot and a strip-panorama taken from that same shot?
So unless you need 35 mm film because that's the only size a particular emulsion comes in, it is easier, and cheaper too, to just use a full frame 6x6 back and crop.
You can travel with Hasselblads, yes.
I have a 'walkabout' kit, consisting of a motorized body, with metering prism, an extra magazine, two lenses (with hoods) and a teleconverter (or three lenses), that does not take up much more room than, say, a Canon 1Ds with a couple of zooms and what else you need to carry with such a thing.
All fits comfortably in a not-that-large LowePro Specialist.
For 'more serious' travel, i change the motorized body for an unmotorized one, expand the kit to 4 lenses, add a short extension tube or two, plus a separate light meter, and put that in a LowePro Reporter 400.
That too is not the largest of bags, but it will hold more film, and all sorts of
extras (maps, note book and pens, and what have you).