Bought this for five quid from a charity shop, spent two afternoons fixing it up in the woodwork workshop at school, and it's now my army transport case. It's 20 x 11 x 11":
When deployed, it stretches to 56" wide, and this is why I call it 'the Galleon':
Currently, it contains my 2000pt tournament army plus a bunch of other models (removed for the pics) and all my playing aids. Here's the left, with platoon infantry, HQ choices and some other bits on one level, and on the other a hellhound, a devil dog, a chimera and a griffon:
On the right, five heavy weapons teams, spare snipers (and other bits) on top of two chimeras, my objective marker and assorted turrets and bits. In the tub are all my veterans, and the multicoloured slottabases thereupon are some playing aides I'm currently working on (vehicle markers etc.). In another pic below you might also see the 5 orange objective markers I mocked up last night.
In the bottom there's stacks of room. Currently, the blue washing powder box on the left holds a griffon and my salamander, and the lilac one on the right has two Leman Russes: