This is quite simply genius. EmojiWorks has created the above range of keyboards that have Emoji symbols on them, alongside letters. There are three models, depending on quite how many Emoji you want access to. You just hold down the EMOJI key to access them, just like you might hold down Cmd or Option.
If I were a gambling man I would bet that all keyboards will look like this within 10 years, although the switch to non-keyboard input might stymie that a little. Still, this is just a terrific idea.