Why not use a piece of 16 ga. sheetmetal with sides turned up and corners welded. Have the fabricator "X" the bottom. Weld pipe flanges in the corners for legs(Or drill/silicone). Weld a bung in the center of the X, drill, and install a ball valve. Done. 16 ga. should be plenty, considering the side would be under 24x36 or so. I would guess your cost would be less than $100.
(Or use 6" pipe nipples and set it on your regular bench, so its not in the way all the time)