I installed a Raspberry Pi inside an old CRT. It's running RetroPi and currently has roms for around 10 systems that support the controllers I have. It can be used as an All In One console using the CRT, or plugged into a modern TV with HDMI to be played on the big screen. It supports wired and wireless controllers (via internal bluetooth).
Raspberry Pi 3
USB extension cables
I used 4in ones to save space, but it limited where I could put the Pi
Micro SD Card
Raspberry Pi composite video cable
Colors on the cable may not match Pi pinout, check before permanently attaching
Screw mount HDMI extension
18" cable to move the Pi's HDMI connection to the back of the TV case
Acquire a suitable TV. I was looking for one that had a relatively large bezel on the front to make sure I could accommodate the USB ports. Initially I looked for portable TVs on eBay, but they were expensive and often shipping was more than the cost of the TV. I checked craigslist and found this TV/DVD combo unit. I wasn't originally looking for one with a DVD player, but I figured it guaranteed me space inside and gave me a place to mount the USB ports on the front.
WARNING! CRTs can hold dangerous and potentially lethal electrical charges even after being unplugged for years. Always safely discharge TVs with the appropriate tools before touching them.
After getting the TV/DVD combo I was thinking I could just rip the DVD drive out and put the Raspberry Pi in its place, but unfortunately the DVD drive was part of the circuit board of the TV. I was able to remove most of the plastic components and ended up wedging the Pi in there, but it wasn’t as easy as I had hoped.
This picture shows most of the DVD drive removed, albeit from the other side.
I removed the decorative plate of the DVD drive from the tray and then cut the front off with a saw, and used it as a bracket to hold the USB extensions. I got 4x 4in extensions so that all of the Pi’s ports were available on the front. They were wedged into the bracket and then epoxied in place using putty epoxy. The extensions were just long enough that I was able to fit the Pi without having to completely remove the DVD drive. Depending on what TV I ended up with I was also considering putting 2 USBs on the front and 2 on the back, depending on the available space on the front of the TV, so the space from the DVD drive worked perfectly.
Once the bracket was back in place in the drive slot, I used construction adhesive to permanently keep it there. Then I used Sugru, a type of silicone modeling clay that hardens into rubber to fill in the spaces between the USB ports and try to make it look nice. I smoothed the Sugru out with wet fingers to prevent leaving fingerprints.