I have sort of skimmed over this post so if I am repeating advice my apologies. Have you considered two drawer filing cabinets with a large piece of marine ply on top?

I have restricted head room in my darkroom (7ft from floor to ceiling) and had to put my Durst L1200 on an 18 inch high coffee table (solid mahogany, weighs a ton). I use it with a Japanese kneeling stool which is surprisingly comfortable.