If you are handy with a saw and a screwgun, homemade sawhorses that are larger than that can be made from 2 x 4 and 2 x 6 lumber that do a fantastic job of tub holding. It doesn't even have to be new lumber if designed to be SOLID. I built a set for my tub work and the local carpentry project robbed them, so I don't know when I will get to actually work on a TUB.
Also a homebuilt roll around cart at an appropriate height will work nicely too. Put a set of cheap casters on it and you have a mobile work table that you can use for all sorts of assembly tasks.
And then.. there are those who have spare frames they mount on rotisseries....
