I made several a triangles out of 1-inch (~25mm) x 3-inch (~75mm) wood with the length calculated for the spread of my light stand legs. At each point of the tripod, I fastened a flange
the feet of the light stand fit into these flanges which kept the feet from sliding off the triangle. Then I used some old left-over furniture casters at each point of the triangle on the side underneath the flange..
This made a very viable, but not very portable, roll-around base for the light stand. But, they didn't cost me anything since I constructed them all from excess pieces (I tend not to throw away things like casters and connectors after dissembling equipment or furniture).
I didn't do this but, you could make the setup more secure with an eye bolt (or screw) near the flange and using some small bungee wrapped around the lightstand leg,
However, if I had seen inexpensive caster sets like these
http://www.ebay.com/sch/i.html?_odkw...s&_sacat=88667, I would not have bothered to fabricate anything!