Custom midi controller built into halloween outfit

djtt community,

I'm in need of some ideas. I'm planning on building a custom midi controller into my halloween outfit this year along with some simple built in speakers. My initial thoughts are to use a 13 inch mbp inside the outfit to run software that will have all the midi mapping to clips. Also, if anyone know of a small in-expensive device that could potentially be used instead of a computer. I would like people to be able to "push my buttons" and that would play sounds

However, I need some electronics such as controller boards, wires, speaker elements and LED's. Anyone know of a good place in SF or the bay area where I can get such gear...or even online? I have quite a few arcade buttons and some knobs/sliders, but need all the stuff underneath.

Any advice, ideas or rants about how stupid this is are welcome.