The Canon 5D with Tokina 10-17 should be actually the one of the best
combinations (with a decent price tag). Using it on a monopod you are
more flexible taking the pictures. A lens ring like from Bophoto.com
or from Agnos.com is better as the NodalNinja.
For bigger resolutions you can always use the Tokina as a full frame
fisheye at 15mm on a tripod with a pano head.
Thomas