Thot:
If you have any suggestion of a multiplexer, and where to buy them, I would greatly appreciate.P.S. I searched the forum but I mainly found references to an 8 port multiplerxer. I could use two, but that would partially defeat the purpose on cutting down on wires going back and forth from Arduino and make it for a bigger daugherboard.
I assume you mean this: http://www.arduino.cc/en/Tutorial/ShiftIn
You won't need more wires, those chips can be chained together so they act just like a 16-channel chip (or 24...or 32....). You just connect the output of one to the input of the next one.