The easiest way to do it yourself is with standard pipe. You can use 3/4 inch pipe (as the smallest) and cut 4 lengths to 26 inches long. Thread one end standard pipe threads.
For the foot, I used 16 inch long 13/16ths aluminum (or stainless) rod inserted into the end of the pipe. This gives you a perfect fit. Come about one inch up the pipe and weld a small block of steel about 5/8" square. Drill and tap this for 3/8-24. Then get a 3/8-24 threaded stud with knob and screw into block and thru wall of pipe. This holds inserted rod in place. On end of rod I attach a stainless steel ball so that it is always making good contact with the ground. The inserted rod gives you plenty of adjustment, I have set up on a side hill many times. Now, buy 4, 3/4" pipe couplings and cut one end off at about a 15 to 20 degree angle. Cut 4 steel plates, 1/4" thick and 4 by 4" square. Drill 9/32 holes in each corner. Weld your coupling to each plate so that the angle is out and forward. Screw base to whatever table you want to use with heavy duty 1/4 inch lag screws or thru bolt with flat heads on top so that they are flush. This base will angle legs out and forward and believe me, there is no wobble at all. I used standard pipe flange at first but found that the threads weren't deep enough for maximum stability and that is when I switched to cutting the couplings and welding them to a base plate. For the top, I use 2, 3/4" layers of exterier plywood glued and screwed together as one sheet and then I cut to shape. Sanding, sealing, and painting with high grade exterior paint is of course recommended. To really clean up the package, you can buy standard snap in broom stick holders (metal, not plastic) and screw 4 sets on the bottom of your table. Then you can snap the legs into them for easy storage and mobility. I always install a carrying handle as well so you can tote the whole thing like a suit case. Give it a try, it works very well.