If you don't absolutely need interchangeable lenses, don't dismiss a TLR. They are light and compact by comparison with the other options. A Rolleiflex is smaller than a lot of 35mm SLRs, never mind something like a Pentax 6x7 -- I can carry mine with a hood, a couple of rolls of film, and some filters in the sort of shoulder bag one would use for a smallish interchangeable lens 35mm camera. They don't need batteries. Although I'm with Chris, batteries aren't a big deal. They last a long time and a spare battery for most cameras takes up less space than a roll of 120. I've never quite understood the fetish on some forums for cameras that don't use batteries.
re: folders -- the desirable ones are over-priced, I think. Although, for what it's worth, I get excellent pictures from a (6x.4.5 format) Super Ikonta. Not quite as good as my Rollei, but decent. However, they aren't remotely SLR like in operation, and they tend to feature small squinty dark viewfinders.