I think I might try a separate repo on fedorapeople, and see if I can get it to work (there are limitations such as filespace that might cause problems). I do intend to follow the suggested naming convention though in case it makes sense to switch back to the canonical repository for some reason.
You can certainly make a "thin" repository that only works if you have .git/info/alternates pointing at a clone of the pkgs.fedoraproject.org kernel repo. I think it might even work to put the URL git://pkgs.fedoraproject.org/kernel in the alternates file, but I'm not at all sure about that.
Thanks, Roland