ok, how about you go as The Economy? We'll wrap you in dollar-bill print fabric, cinching in mid-thigh, where we'll use a hoop and a little craft foam sheeting and paint to make a big old drain. you could even have a drain-themed bucket if you plan to trick-ot-treat.
(hell, you know it might be cheaper to tape the Washingtons together than buy the fabric....)
alternately you could go as a clown car......