freqflyer, although not answering your question, here's what I do: with the rear seats pushed upright, two Rubbermaid Roughneck boxes (one 18gal tall one and one 14gal slightly less tall to avoid handle interference) fit in there nice and snugly and still leave some floorspace in the aft end between the boxes and the rear hatch. These containers don't move around and are great for storing headrests and groceries and keeping stuff contained. Although I don't use it, a lid on top of each box would keep out prying eyes.