Thanks everyone, for the information. It's really helpful.
Actually, that's a thought. It's one reason that the Bessa still appeals. I have a couple of Canon rangefinders and a Topcon RE2, all in working condition. But they are like carrying a brick. I'm after a camera that works and feels good (and I heard that the OMs are reliable - even though I've factored in CLA costs and time).The single digit OM bodies are wonderfully compact, but they aren't as light as later, more electronic cameras. I have a couple of Canon EOS film bodies that are a fair bit larger than my OM bodies, but a lot lighter than an OM1n or OM2n.
Digitally, I use a Nex 7 with the Zeiss 24, after giving up on Canon SLRs for the bulk/weight issue. So I don't really want anything heavier or bulkier than that.