I have nothing new really to add ... Besides that I have a Pentax 67 and a Bronica GS-1, and while the Bronica is lighter than the Pentax 67, it's still pretty heavy. So if you really need light, I'd say you have to go with the Mamiya 7 or one of the Fuji rangefinders. They're all pretty pricey though. But the Bronica's have really good grips IMO. And if you slap a grip on a Bronica, they're pretty easy to handle and you still get all the flexibility of a slr vs a rangefinder. Not to mention the GS-1's are less than half the price of a Mamiya.
Also, if you want to buy a Bronica GS-1 to test it out, I have one for sale in the Classifieds. I ever have a 65mm lens that I could package with it