*thud*
You guys you guys you guys! Look at this HUGE series of medieval music repertoire! It's mostly 14th- and 15th-century, but I see a few volumes of earlier stuff in there too...
Corpus mensurabilis musicae at the UPenn library I don't have borrowing privileges at Penn at the moment, but El Grande Instrument Pimp says he'll retrieve the 14th-century Codex Reina volume for me and who knows what all else for himself... wheeee!
ETA:
momtoast, there's a volume on the Cancioneiro de Elvas in there. :)