This post is a bit late in coming, but better late than never, right? I was able to attend BrickCon in Seattle for a day, and got to see lots of cool mosaics. The winning mosaic in the large category was called "Remembering 9/11" by Mariann Asanuma (Model Gal).
I'm very impressed by the complicated techniques used to render this image. There are plates and bricks heading in all sorts of directions, which allows a greater amount of detail to be used. Mariann said this took her 100 hours to make this, and I'm not surprised.
I first saw this mosaic on Mariann's blog, Model Building Secrets. You can find her original write-up on it here.