I like the idea of using a MIDI trigger pad for things like keyboard shortcuts or text snippets. I'm sure you could make something similar on the cheap with an arduino.
The form should limit the number of digits allowed in the "I want to spend" field. Right now, it says I'll receive more bitcoins than the total possible mined coins cap (21 million). http://i.imgur.com/pCUTqOz.png
Obviously it's a mock form, but shouldn't it at least be accurate?