I have a bunch of these excellent industry grade Densei-Lambda (now TDK-Lambda) ZWS150AF-5 switching power supply units for sale - they have been removed from fully working LED display cabinets (the kind you use in LED walls). They are 100-240V AC input and 5V / 30A output, that is a whopping 150W of output power at 5V! These will power any MIDIbox project with ease, no matter how many LEDs / displays you want to use… Cable harnesses included as in the pictures. Asking price is 15€ each plus shipping. Located in Germany.
A data sheet can be found over at Mouser: ZWS150AF5/J Datasheet (PDF)