When you are working up special items for holidays like Zilloween, I wonder if you might consider releasing "special" holiday bags, by which I mean 10- or 16-slot holding bags but in holiday-themed colour schemes.
I would love more colours of bags in order to make sorting things easier.
You could release special bags during the holiday period: they might be available for sale from certain vendors, or even be a craftable item. They could also have a quest element like the Zilloween candy giveaway, possibly something like you can't buy for yourself, you can only give away to other people (or else, for example, they disappear after the holiday; or, like the captured pig escape factor, maybe you can only hold a "new" bag before they, um, escape.).