That would be a great little project. Check out the new pi3, it has built-in Bluetooth now. Maybe you can use Bluetooth to make a wireless controller.
I'm using a pi2 to build a whole house home automation system. Very powerful little computer. I've also done work with Microchip's PIC. It's amazing how powerful computers have become since I started programming in assembly on Motorola microprocessors 30 years ago.
My idea is to have 12 footswitches the function of each one defined purely in context. Any switch can potentially do anything, including redefining what any of the other switches do. As a "for instance", imagine that define a button to put the unit into "pick a key mode". When you step on it, all 12 buttons change over to a single key, from A to G#. Then, when you step on one of them, it picks the key and all of the buttons go back to the way they were set before "pick a key mode" was engaged.
Of course, to do that you need to have a separate LCD display for each button so that you can show the user what the buttons currently do. It turns out that you can buy 16x2 LCD displays for about $2.00, and then another $1.50 will get an adapter board to put it on an I2C bus. I was also going to put on a couple of rotary encoders that would need LCD displays as well, and then a master display to show general info. So that's 16 displays in total. Most of the I2C adapter boards only come with 3 bits of address jumpers, so that means I'm going to need to use a I2C multiplexer to run two display buses. Which gets a little challenging.
Then I decided that each switch needed to have an RGB LED associated with it. I don't know why, it just seemed like a good idea. This turns out to be the most complicated part of the whole project. There are RGB LED's with built in microprocessors, but the timing requirements exceed what the Pi can do reliably. So I've picked up an Arduino board for that, and I'll probably connect it to the Pi through USB, which should make it easier to reprogram on the fly too.
I figure I'll stick a WiFi dongle on the Pi, then I can program it from anywhere.
The only things that have me worried are the boot time of the Pi, and the strength of the enclosure. Hammond make a 20" wide slope-top enclosure that looks about right, but I'm worried that once it has 16 LCD screen sized holes carved in it the structural integrity will be compromised. I guess I won't know until I try it.
