THIS IS NOT MY CREATION -- I JUST TOOK EXISTING FILES AND MODIFIED THEM TO BETTER SUIT ME. The original files are designed to be CNC machined and thus required several modifications to be 3D printed. In addition to thickening certain parts, I also made the screw holes bigger so you can thread the screws directly into the plastic without having to tap threads. I am still working on tweaking the files to make for stronger prints. Additionally, I'm working on a new design that anchors the console to the bottom housing instead of the faceplate and then the faceplate just "snaps" in. That should make the console more structurally sound and make this easier to print but I am still using the gb9k files as a base.
Please see the following page for the original files: https://github.com/gb9k/GameboyMacro
There are two versions of this faceplate, one with four face buttons (like the original DS Lite) and one with two. I have only made the modifications to the two button faceplate but it you drill out the holes (or just insert the holes in the STL before printing), you should be able to use all four buttons. This design requires you to remove the touch panel on the LCD.
I have uploaded two versions, both 2 button style. One has the charge port blocked off (which is what I used since my Macro has no charge port) and the regular 2 button adjusted file. I'd recommend using a transparent or semi transparent filament for aesthetics and to allow the LEDs (for charge and power) to shine through but any color should work. However, I do not recommend printing this with PLA. PLA gets brittle over time and your screw posts will snap off and then your console will fall apart. I'd recommend printing this in PETG (which is what I personally used) or ABS and 0.1 mm layer height is fine. I printed this with both a 0.3 and a 0.4 mm nozzle with no issues. I highly recommend a glass bed and printing directly onto the bed with a skirt or nothing. A brim may be difficult to trim off the screen bezel and a raft will give the faceplate an ugly and unpleasant texture. I printed at 100% infill 0.1 mm layer height and 0.25 mm initial layer.