So it turns out 13,000 pounds of very small rocks are just as heavy as 13,000 pounds of soil (though their volume is bigger, meaning we can grow more in them).

Dan writes:

Thanks to everyone who came out, especially Mike Phippen for bringing the crane!  We managed to get all the materials up on the roof and in place, including all the “paks” of rocks.  We still need to cut into the bags and actually plant the plants, but the really hard (and it
was really hard!) work is done.

Here are some pictures from the big day:
http://s486.photobucket.com/albums/rr221/DanKorn/?albumview=grid

Some sample photos:

rolling root barriercrane with pallet roof levelcrane with pallet street levelthe plants are on the roof as well