Oh

Sorry if you already tried these things, but is it possible to abandon the quest and restart it and/or go back to the NPCs and talk to them again. Looking at the dialogue of the quest it suggests going back and talking to the NPCs (weavers, goldsmiths and leatherworker guilds) might give you another:

Serendipity: "Wow, you really are as foolish as Red said! He came by earlier and gave me additional mortarboards, saying that you'd probably come back and ask for another. "