> which distfiles can be deleted. The GPL requires every binary package
> be "covered" by the distfile that generated it, and then again for
> three more years after the binary package is deleted. I've been

I believe this is not true.  The 3 year period only applies if you
distribute binaries under option 3b.  If you distribute under option 3a, it
is sufficient to provide source only as long as you provide binaries.  You
have to provide source "from the same place" if you want to distribute
binaries from an FTP server and use distribution option 3a.  See also the
GPL FAQ:
http://www.gnu.org/licenses/gpl-faq.html#SourceAndBinaryOnDifferentSites

     christian