Ok, ok. So it's not that hard to make a pack cover. This one sports completely-waterproof fabric (still lightweight though!), and shrinks and grows with a full circumference elastic drawstring. Packs down really small. Sized to completely cover a fully loaded Terraplane. Wrap-under bottom lets you put your pack down in the mud with little soakage, but there are grommets down there so that the inevitable dribble of water that comes in the sides gets spit out (otherwise you end up lugging a pond around in the bottom of the pack cover).