I dumped my entire svn trunk checkout of rockbox and started with a fresh checkout. Then, I stepped through the recipe again, and everything is coming out correctly. rockbox.mi4 exists and the entire .zip file installs beautifully. I like the new usb capability. Awesome. Now I'm playing with some of the patches. I've already been successful with the anti-alias font patch. This looks like it will be fun.
I'd like to thank everyone for your help. It made me realize that sometimes it really is because the original files were corrupt.