After working on this in my copious spare time the last year or so, it is ready-ish for general consumption: Chord Practice App
Guitar learners run across a technique for increasing dexterity and finger accuracy called the "60 Second Switch" practice. I like to track data for some reason, so when I first started, I was entering my times into a Google spreadsheet. But as I learned more and more chords, the spreadsheet became more of a pain in the ass than a help. I envisioned a mobile-friendly web application I could run on my phone to record my 60 second switch practice times and then chart the progress.
Chord Practice is the result.