I need to dig into how these are created. A minimal debian install, with nothing besides the base, requires more than is needed. For example, it installs aptitude. While nice, its not necessary. And docs, those are of course nice, but not necessary.
And what about installing the base to a compressed image, using squashfs? That would be awesome. It could be merged with unionfs so that part of it could handle package installs. Interesting idea.