Have a look at the Retrospective 5 or 7 from Think Tank. No - not the lightest, but very nice material and somewhere between stiff and huggy. Very well thought out interior too. The dividers seemed to have about the ideal thickness.
I have both of these. At first the Retrospective 5 seemed a little too tight. It was hard to get into the small front compartments when the main compartment was filled with gear. In fact, I took it back--then changed my mind and bought it over again.
It
is a little tight. The good news is I can get a lot of gear into this little bag! Recently I carried a Leica M with 40mm lens on it; an extra lens; an X100; a Digilux 6; 4 extra rolls of film; smallest rocket blower; microfiber cloth; lipstick brush; notebook; extra batteries for the digital cameras and the Leica. It has little pockets for the digital batteries. Oh, and it comes with a rain cover, and that is in there, too. So the small compartments are a little fiddly, but the good part is that if I'm willing to fiddle, I can carry a lot in a small bag.
The rain cover seems a little tricky--I think when the time comes that it starts raining, by the time I get it on, the rain will have stopped.
I bought the Retrospective 7 after watching Mike Thomas' excellent review on YouTube. Mike showed that it makes a good Hasselblad bag, and I bought it with
that in mind. I will give the 7 a field trial this summer.
Update: They came out with a Reto 6, and I bought it. It is like a "Retro 5 Stretch model." It's a bit longer than the 5, just long enough to allow one extra compartment; and comes with an additional divider to allow four compartments to the Retro 5's three. It's also deeper in the front-to-back dimension, just deep enough so I can get in two M lenses. So on a recent trip, I took an M7, M9, and 21, 28, 35, 50, and 90mm, plus film, filters, etc. and it all fit. Good bag. Good bag!