This enclosure accommodates a common AC to 5v (5A & 8A) PSU from ebay/aliexpress, and a Raspberry Pi 2 and Raspberry Pi Model B+ (probably Pi3 too, but not tested yet).
http://www.ebay.co.uk/itm/191733870857 - 5v 5a/8a - 110mm78mm35mm

The Pi is my HTPC running OSMC and my intention was to provide enough amps to run ambilight/hyperion/boblight LEDs and keep cable mess to a minimum by integrating the power and pi into one box.

The area above the Pi provides space for a prototype circuit - Arduino Nano, Pro Mini, or a logic lever shifter like I've done.

Still to do:

• Design mounting system (VESA possibly).

UPDATE:
V4:

• Airflow slots at the PSU end and in the proto area.
• Dowel ridge around the sides of the case for better alignment of the 2 halves when screwed together and for strength (very loose tolerance at the moment).
• Re-designed bottom vent holes.
• Mesh now as tidy as I'll get it.
• PSU moved 1mm closer to the side to give more room for cables on the other side.

UPDATE:
V3:

• Tidied mesh some more.
• Fixed the ethernet & usb ports area so it fits the Pi nice.
• Added hole by the USB ports for running wires out of the case.
• Changed the fan hole, to accept any fan between 30mm and 60mm. Note: if using one of the smaller fans, there will be large holes around it.
• enlarged the holes around the USB power, HDMI and 3.5mm jack ports.

UPDATE:
V2:

• Added 4th screw hole.
• Pi has been moved 6mm up to make space for 4th screw hole.
• Enlarged screw holes for larger head screws (9mm head will fit)
• Mesh is a little more tidy, more dimensional accuracy.