I found one of these old LCD handheld from the nineties for a couple bucks in great condition, and thought I might be able to turn it into a retro game machine for a xmas gift for a friend who is a huge star wars collector. I loved how it turned out! (and I think he did too) it's a little tight inside with a 3000mah battery stuffed in there, so a slightly smaller one would've been smarter, but i was able to get everything to fit without too much trouble, even if there might be a bit too much hot glue for some people.
I took a little inspiration from the MintyPi 3 and also stuck a Hall Sensor in there, with a little magnet glued inside the lid, so that when you close the lid, it initiates the software shutdown and then powers down the pi and other components.
Other highlights include 2 external usb (but i did do micro so that they would fit easier, so you need an adapter) as well as A/V out at the headphone jack, so you can use a splitter to plug into a TV with composite and audio, and then plug a couple controllers in, and you have a tiny console as well.
I reused the button boards from the original game, but they aren't a common-ground style, so I had to slice it up a bit with an exacto knife, and reroute a few of the connections for it to work, but I was able to do it with only a couple added wires in there.
sd card access is through the original battery compartment. the red button at the top is the power on/off switch (using an adafruit power switching circuit). most of the heavy lifting is done by the pocket adventures board, which has the usb hub, audio adapter and amp, and easy connections for everything else. finally, i tucked one of those little ads1015s in there to monitor the battery, and use one of those 3-way toggles for volume and icon toggle.
adafruit push button power switch
pocket adventures audio jack
generic 5v boost and recharge
micro usb ports
volume and hotkey toggle switch
2.4" SPI screen
pocket adventures SPI adapter
23mm 8ohm speaker
magnet (for hall sensor)
barrel jack for power
LEDs for charging/charged indicator