Cheap, easy, effective...
15 3/4 x 21 3/4 x 7 7/8 inches by Clear Stack. (a WalMart purchase)
Comes with it's own semi-opaque lid, but I had a piece of plexiglass and a clone-dome cover handy.
About $5.00 each in a 3-pack.
Drainage rocks in the bottom of the box, rather than the bottom of each cup.