Tomorrow I'm putting my turt in his new tank. This is a picture of his old basking spot (that was always partially submerged) on top of the new one that took 2 months to build. The picture doesn't do this bad boy justice.
squirt, I would probably not go my route, but instead use pvc and essentially build a cube. Lay a slate/stone tile on top and you're pretty much done. You only have to find a creative way to build a ramp. I made two in under an hour and didn't spend $20. I was just experimenting and didn't really know what I was doing at first, however, the pvc dock I made was way better than anything I could buy. Im sure someone here can give you more specific details. Good luck!