As someone who has done this for 5+ years now (before that 10 years at various large / medium corps. and startups), I'd advise you that you won't find good opportunities via Dice and Craigslist. Nearly all of my contracts have come from references / networking (i.e. people I worked with once who hire me back as a consultant to build something / solve a problem). You're just looking in the wrong place.
So, general statements about how contractors should make approximately double their per-hour salaried rate only apply to people with a sufficiently established network of paying clients.
I don't know, I don't really consider it "normal" or "market rate" if there isn't an open market for it.
I appreciate your wisdom, though, don't get me wrong. It just makes me question the typical advice espoused by people.
