Actually, I think a glass crate could work pretty well. If we don't give it any color, but rather make it transparent against the background, it would work very well, I think. Just a white border, and a little white shine or something should do the trick.
I agree with Dekudude's post... someone should try drawing it. edit: @jell, or maybe it's some kind of plastic they invented?
Btw, we could either rely on Flash to handle transparency (which takes up quite a bit of processing power if you have even more transparency around it), or we could try to copy what HATPC did with water, and fake the transparency effect. In fact, it could add to our art style
My problem with wood is that this game is set in a post-apocalyptic, futuristic world. They probably would use mainly metal in the time, and the little wood that has been used has probably rotten away.
Screw that. Let's just use wood, I mean really. We'll throw in a wild-life reserve or something, and that's where they sometimes get their wood from...
Those wood crates are very good. My only complaint is that it seems like, by using them, we're getting too close to ripping off HatPC. Aeon is an original game. Though Aeon will have similar qualities as HatPC, it isn't generic. It's name-brand original. That is why I think we should use something like glass, to be more original.
With that said, here's Sketch #2 for glass. I used the metal crate, and made it transparent and white. Mainly.
Try viewing that image on different background colors.
You could make some backgrounds for the levels. If you only have paint, download GIMP. Most of the time, we'll just need some nice patterns that look like sky or metal.