I'm late to the party, but I have added 7 raised beds to my yard since moving here in 2007, and I stopped de-turfing it a LONG time ago. Layered cardboard kills the grass/weeds (wet the cardboard/newspaper as you lay it out), and acts as a weed barrier. I built a raised bed a couple years ago with almost no dirt. It's 6 landscape timbers high, and I filled it with brush and yard waste (this would take too long for you, probably), then covered them all with cardboard/newspapers and about 3-6 inches of soil. The yard waste will decompose into fantastic soil, and even though there's minimal soil in the bed, my dayliliies are beautiful, and have long healthy roots. I use Preen as a pre-emergent, and that bed has very few weeds in it.
I collect all my office paper/newspapers/boxes, etc, and store them until I need a weed barrier or a new raised bed. Then I put them to use.
