Yeah, I'd came up with a few things a little while back. Most of them were made from $1 bills. Designing isn't too bad, if you can do it from a crease pattern. There are a few web sites that show how to do it. Eileen Tan has some really good tips on how to create from box pleats and circle packing and Robert J. Lang has a program on his website, that's free for download, that'll create CP's for you, using the most efficient use of paper.
I never could get that to work very well, though. I usually just start folding, get to a point, look at my paper, and find something that I can make out of it. I bought some paper making supplies, and I'm going to try and make another model I did a while back. I'll post pictures if it turns out any good.