I decided to bite the bullet and just make the stands from steel despite the high cost. First task was to make the design in CAD so I could start a shopping list.
Much of the steel stock that goes into this has been
running at about $20 per foot lately! But I found a local scrap yard
that has a selection of some of the right sizes though at a more
reasonable $8-$9 per foot. Still about double what I would have paid a
couple years ago.
Got the two crossmembers framed out. These are 2.5" x .12 wall square tube. Casters are 6" diameter, double locking, and 1350lb rating each. Overkill, but I want it to be easy to roll.