Thank you all for your input! For the record, Chris and I went to Wal-Mart and purchased:
--A Rubbermaid "Duratote" 83L bin
--Two Plano model 3750 tackle boxes. They are flat, about 13 inches long--long enough to hold the long bars, but not the long angle bars. They have lots of adjustable compartments.
The tackle boxes and everything else fit in the Rubbermaid bin. While we were in the store, I wondered if the bin was too big. Room for expansion is good, but space for storing bins is limited.
Sure enough, the bin will not go into our Saturn's trunk upright. Of course we found this out AFTER we'd paid for the bin.
Then again, we weren't planning to take the VEX kit anywhere in the car with us--or were we?