I have an old Rolleiflex Automat which I got for about what the RB67's go for, and its a great camera for lugging around. It is much smaller and lighter than Mamiya's TLR's, and much much smaller than the RB/RZ cameras (The first time I picked one of those things up, I thought I was holding a brick instead of a camera).

The only problem you'll probably have with a Rollei is the lack of interchangable lenses, and I don't think the wide angle Rollei's are exactly cheap. You could consider the Mamiya TLR's, but those are pretty big too.