I've had an old Casio CA-100 Tone Bank Keyboard for years now, I must've found it at a yard sale because it's dented up and missing pieces. For as long as I can remember I've had to toggle the sharp numbs where the switches once were, being that I was missing 2 / 3. After getting a 3D printer I decided to test my skills and design a replacement switch. 

I must admit, it doesn't fit as well as the original I use for my power button, but in a bind these replacement switches will get you by. Don't be afraid to comment and offer some advice on how to make these a bit more stout.