The Game Boy Pocket Colour is a popular mod that puts the Game Boy Colour in a Game Boy Pocket shell. It's almost become too easy of a mod, with so many options available.
For the longest time, I've wondered if you can do the same with a Game Boy Advance and a stock Pocket shell. Spoiler alert: you can't (no screens fit in the shell). I didn't know this until I tried, so here's my attempt just to bury the speculation.
A while ago, I reverse-engineered the AGB Game Boy Advance, so I already had all the schematics and footprints drawn up and ready to go. I changed the circuit slightly, modernizing its power circuit and added a rechargeable battery to it. I also removed all the original screen circuitry.
For the cart slot, I needed to use a DS Lite/AGS cart slot since its narrow body would fit the shell. It needed to sit higher on the motherboard and also closer to the edge. This is because Advance carts are shorter than original Game Boy carts. I ended up using header pins, and it worked well.
V1 of the board worked!
Here I am testing it with a laminated kit. However, none of the Advance screen kits I had on hand fit in the shell. I searched for the smallest kit on the market, which is the Cloud Game Store kit.
Since even the smallest kit on the market didn't fit in an original shell, I used Joseph Tompkins’ Pocket shell files and cut away as much as I could to fit the screen. This led to some of the walls being less than 1mm thick.
The only issue was the screen connector didn't line up with the Cloud Game Store kit I used. So I made my own ribbon cable.
So I ordered the new ribbon and got a resin print of the shell made.
This is kinda where I dropped the project. To fit the screen, I had to remove 4/6 of the screw posts used to hold the front and back shell together. I designed a wall with screw posts to sit on top of the panel, but due to the thickness of the panel, the screws would only go in a few millimeters.
It could be achieved using a Game Boy Micro screen, but that kinda sucks.
In my opinion, there was no use continuing for many reasons:
1. I couldn't use the original shell.
2. If I was going to use a 3D print, I might as well redesign the whole housing.
3. I like horizontal devices, and the original Game Boy Advance is one of the best horizontal devices.
At the end of the day, this was a side project. I thought I could be the first person to make a Pocket Advance but alas, unless we get a smaller kit on the scene it isn't happening in a Pocket shell.