Not the most brilliant idea I've ever had, but I just got a copy of Tales of Phantasia and unfortunately I had no where to put it, but as luck would have it I found an empty DS case the other day and totally forgot about it.
I decided to make my own variation on a DS template that I found here that was made by Sarashi, I didn't do much to change the overall design. I only changed the DS logo on the cover and spine to read "Nintendo GBA". And I also changed the back to have GBA related info instead of DS Wi-fi info
All of the text, rendering, the Namco dev logo, barcode, and screenshot borders were done by me.
Although the borders do kinda look like they could use some reworking.
[This was heavily inspired by the official US GBA cover to Tales of Phantasia]
US Tales of Phantasia GBA Box scan: http://i.imgur.com/q3MhM.jpg