This is a pretty horridly-thrown-together app to generate sprites for keys of a keyboard, so that I could avoid doing it manually for our game.
You need to provide it with a list of keys to generate. You can edit /Data/Default.txt, or just change the text in the app. Each line represents a key. The format here is [filename],[display text]. If [display text] is missing, then [filename] is used for what to display on the sprite. The output files will be transparent PNG's.
For each key, it will decide between two button templates to use (small/medium) found in /Data/. You can edit those to match your game.
There is a pre-compiled version here