buy the plastic tubs....
get a couple smaller ones instead of a 4x4 though- 2x4 fits in the back seat of your average car. 4x4 does NOT.
I have actually a 1x4 for my veg closet and LOVE it. I like knowing that if I have to break down, all my equipment is small and can be bagged, boxed, stuffed, packed, and driven to a storage unit with a minimum of exposure.
Build your own tables for the tubs though. A few 2x4s and some sheetrock screws and yuou're in business.