Sent mine in yesterday -- like anything done to a deadline, there are a few things I would probably have done differently/better if I'd had more time, but on the other hand if there hadn't been a deadline I might not have done it at all, you know? I definitely had a great time making the piece.
In one of those little bits of innovation that happen when you're trying a project like this, I came up with a technique for turning scrap material from my work into terrain as a sort of side effect of the main thing I was building; I'm now going to use it on half a dozen or so new buildings. I'm quite pleased by that!
Many thanks to Brian for running the contest, and I'm really excited to see everyone's work!