Here's a thought, two different products for two use cases.

1) A custom art cover: A Purchase option that allows for corporate branding for promotional events and corporate team building events or just individual customization. The option would allow a buyer to upload an vector image or limited size to be printed on the cover of the RocketBook products.

2) Cover Sleeve: Much like regular 3 ring binders have sleeves for inserting pages. This would allow something similar to the idea above, but less permanent. Kudos for people who draw the art in the RB product, scan it, print it, and insert it as the cover page for their RB Product (Recycle).