Before I start: No, there's no actual game in development.
I was bored one week and looked up screenshots of the GBA PS collection, where apparently they just shrunk the content shown on the screen for each game. Shrinking the text box borders, spacing between text lines, or (in my case) taking one tile line out of the character sprites.
The only real change I had to make to accommodate the GBA's smaller screen size is to reconfigure the party's stat box at the bottom, but it came with the nice benefit of increasing the name space by one letter!