Glamour Plates suggestion
How about instead adding new Plates generally, giving each class/job one plate for them and let the other plates how they are? with this you could have a specific design for your class/job and still have all the other plates for free designs. I mean i want each of my class to have a different design but this would suck up all Plates in the end and i dont have leftovers for non class specific designs.
It doesnt need more then one specific plate for each one (Battle class like blm,ast and Gatherer and crafter) Maybe bound at the saved set.
Dont know if this is possible and how much capactiy it would take in the end but it wouldnt be an idea or?