Bought a mobile base for some of my power tools.
http://www.harborfreight.com/catalogsearch/result/?category=&q•288 $ 34.99 at my local store. (Compare to circa $90 elsewhere)
After assembly and try-out, I went back and bought 4 additional bases.
While skeptical at first, I was impressed with the quality of this design. The metal components are well designed and strong. Probably 14 ga steel. You provide your own spreaders for which I ripped 1-1/4 " lumber from framing studs. The instructions call for hardwood, but the metal brackets take almost all of the load. The purpose of the spreaders is, well simply, to spread the brackets out for the width and length of the tool.
The unit is rated for machinery up to 300 pounds. That's 75 pounds per leg. I think it could hold a lot more. I bounced up and down on various corners (adding 250 pounds to my band saw) and saw no damage or deformation of the unit.
When assembled and installed your equipment will have been raised a little more than 1/2 inch off the ground. Almost un-noticeable.
While I am usually very cautious with my expectations of HF tools, this one certainly will serve me well. As usual, I have no relationship whatsoever to said vendor.