Doug Burnside has already done this, if I recall correctly. Just use an inkjet to print his template onto your own sticker material.

Remember that it's not just the button faces that have different printing on them. The buttons themselves do different functions depending on which remote you're using. A new sticker won't magically give you a feature that's missing from the Kenwood remote.

Also, the sticker material will wrinkle a bit when applied to the remote, and will tend to wear out pretty quick I'm guessing. But I don't see any reason why you couldn't use Doug's template or make one of your own in any drawing program, then print it on your own printer.