3D printed arcade machine designed for using the following components

• RPI 4 (or you can use a slim fanless nuc like a Z8350 or similar)
• 18.5" portable monitor (Coolhood brand i used but others likely work)
  • 180 deg USB C adapter
  • 180 deg Mini Hdmi to Hdmi adapter
• Ugreen USB 4 port hub
• Ugreen 65w Desktop Charger
• PAM8406 5w Amp module
• 3.5mm Audio Ground Noise Loop Eliminator (any that's good), cut the RPI noise.
• Mounted speakers ~40mm (see my mounting hole template).
• EG starts 2 player joystick and buttons kit
• M3 bolt, washer and nut kit(s). Also get a standoff kit for mounting the PCB of the RPI 4, joystick controller boards and PAM8406 amp.

Couple points

• To achieve the required size, i had to panelize the design into splits. Once assembled and bolted up, it is quite sturdy. Splits are staggered where i could.
• I've managed to avoid having a fan with the vents in the back and using a portable monitor. 
• All items run on 5V (or USB-PD) from the desktop charger. I also believe the use of components that are generally low power keeps the heat down to not need a fan.
• It gets a little cable crowded but it all fits nicely, selecting short and flexible cables is ideal then zip tie them up.
• The joystick panel joint/support part is designed to just rest inside the machine. It's bolted to the joystick panel but rests on the bottom panel when installed.
• The nuts are largely to be pressed into the nut recesses. 
• Mounting the amp will be a bit of a trial fit approach. 
• I found RetroPie to be very good both on RPI4 and on x86 with Debian.
• You can use one of the spare arcade buttons (assuming 6 button joystick setup) as a power button, this is why there is a hole in the side.
• The PAM8406 amp board volume knob also acts as on/off. Great for turning off the amp when the rpi4 or PC is also off.  
• 3D filament wise, your preference/choice here. I quite like PETG or esun PLA-ST / Polymaker PolyMax PLA.
  • This is what worked for me, if i had an enclosure, i would likely gone down other materials but i like simple printing.
• This is going to consume allot of filament and time printing. Pros/Cons, if i had access to my old workbench/garage/tools etc, i'd likely look at MDF, PVC, Acrylic and anything else i could cut/mill out without panelizing. That said, the ability to print mount points into the parts, vents, hole positions for buttons etc and then just bolt up also is a big win.

Product links or product names below for items i needed in addition to the RPI4

• Amazon.com: COOLHOOD 18.5 Inch Large Portable Monitor for Laptop, 1080P FHD 120Hz 125% sRGB USB-C HDMI Travel Monitor for Laptop Mac PC Xbox PS4/5 Switch, Portable Screen with Smart Cover, VESA Compatible : Electronics
• Amazon.com: UGREEN USB Hub, 4-Port USB 3.0 Hub with 3ft Extension Cable, High-Speed Portable USB Splitter for MacBook Air, Mac Mini, iMac Pro, Surface Pro, XPS, PC, Flash Drive, Mobile HDD : Electronics
• Amazon.com: UGREEN 65W USB C Charger, Nexode 4-Port GaN Charging Station with 2 USB-C and 2 USB-A, Power Adapter for iPhone 16/16 Pro/15, Galaxy S24 Ultra, iPad Pro, MacBook Pro/Air, Steam Deck : Electronics
• Amazon.com: DROK 5W+5W Mini Audio Amplifier Board PAM8406 DC 5V Digital Stereo Power Amp 2.0 Dual Channel Class D Amplify Module for Speaker Sound System DIY : Electronics
• Amazon.com: EG STARTS 2 Player Arcade Games DIY Kit Parts 2 Ellipse Oval Joystick Handles + 20 LED lit Arcade Buttons (Red & Blue Kit) : Video Games
• Amazon.com: Mywish 550Pcs M3 Screw Metric Screw Assortment, 304 Stainless Steel Hex Socket Button Head, 3D Printer DIY Metric Bolt Assortment, Flat & Spring Lock Washers/Nuts/Hex Wrenche M3*6/8/12/14/16/20/25mm : Industrial & Scientific
• Mini HDMI Male to HDMI-compatible 2.1 Female Extension Adapter 360 Degree Angled U-shaped Converter (Up Angle)
• WM-101 Type-c male to female data fast charging cable U-shaped elbow
• 3.5mm audio cable
• 3.5mm Audio Aux Cable Anti-interference Ground Loop Noise Filter

NB.. I'll get around to adding more photos of the final build and some more comments but the above is a large part of it all.