In the last few years they have been recommended by many people for this exact situation, to avoid digging a 3 or 4 foot footing. I haven't paid a huge amount of attention to the details, but would assume the advice would be to reinforce the heck out of it. Nobody puts in a footer for a driveway, and they hold up pretty well without a ton of rebar. Like I said, logically it does make sense that with a bunch of rebar to give it some tensile strength the slab would float. That's why I'm curious to hear Tom's opinion of this one. I'm looking to move in the near future, and odds are I won't have a concrete jungle in the backyard of the new house, so I gotta start paying attention to this, lol.