Wow. This is extensive. I've only got one question (not asking for help, just clarification).

When downloading, say, for Ubuntu's Gutsy repositories (this one was designed for Edgy, but it's all the same) does apt-sources download all the architectures (i386, amd64, powerpc and sparc) as well?

I don't see any text that just calls for a single one such as just i386.