The RPM Guide http://fedora.redhat.com/docs/drafts/rpm-guide-en/ should document the %{SOURCE1}..%{SOURCEn} macros when describing the "Source0:" .. "Sourcen:" tags. (stickster told me to file this here)
This bug remains open in a NEW state waiting for a maintainer for the RPM Guide.
Moving to the new rpm-guide component to help in finding and resolving all RPM Guide bugs.
This guide is being resurrected. Reassigned all tickets to developer.
This has been open for too long, we are not actively maintaining this guide.