Basic Sumo Rig
Ok, it's not all DIY, but the company 'Shape' is slashing their base Shoulder Support used for their 'Sumo' configuration. The basic Sumo configuration (above) which is a shoulder support, counter weight, and handles will run you $459. The simple dimple shoulder 'base' (below) itself normally runs you $199.
Right now (limited time), Shape has slashed the price of this base foundation in an eBay auction to 'a third' or it's normal price. Hey even on my best day at Home Depot, I don't think I can make something as pretty for that price. Next jump on over to the B&H website where you can grab that pretty little padded 4lb. counterweight for just $69 bucks, and you're good with a very professional looking solid foundation to DIY on. All you're missing is a set of handles, which shouldn't be too hard to craft up.
Shape 4lb. Padded Counterweight for Sumo