Yeah, right - the scales themselves are pretty much the business end of this. Here's what I've got so far, in Sketchup:
These things are going to be out in the weather with about 70 pounds sitting on them, so they need to be stout and weather resistant. I'm welding the upper and lower frames from 1.5"x1/8" angle iron and filling in the space with sheet steel - I show it as diamond plate, but it'll probably be just plain sheet steel, like 18-ga. The load cell will be anchored to the base with sturdy bolts, and the live end will support the top. There are four posts on the inside of the base that stick up into four tubes on the underside of the top to act as guides. The base also will have a small plastic case for the HX711 amp.
I'm going to try to provide a weather seal of some sort between the top and the bottom. The whole thing will get at least a good couple of coats of paint, or I might have it powder coated. We'll see where the budget takes us.
I'll probably start knocking these together in December - I've got some vacation time that I've got to take or I lose it, darn the luck.