[croddin]

If my math is right, a keyboard with every currently defined Unicode character would only be about 16 feet by 16 feet. Someone should make one.

[JazzXP]

Not quite that, but Tom Scott did an Emoji Keyboard that was spread across 3 or 4 keyboards.

[roywiggins]

Here's one that has all the important Unicode characters...

well, all the emojis.

https://www.youtube.com/watch?v=3AtBE9BOvvk