Funny you should post now. I'm coming to Dallas tomorrow to buy a DHS.
Here is a picture of the water pump socket I made, so you know what your looking for.
http://www.geocities.com/grandolfo
You can get a cheap one (stamped steel) made by Lysle for about $20 from many online tool stores. The tool warehouse comes to mind. Some have said they tend to slip. You can get a good machined one like mine for about $80 from Snap-on or Kent-Moore, or you can rent one from Bruce at Caddyinfo. He changed the site and I can't find the link so you'll have to search around or email him.