BEWARE, THIS DOES NOT WORK YET.
Uses the numpad with classic cellular phone style letters assigned to the numbers.
Poke the "2" key twice and it makes "B".
Poke the "2" key twice and it makes "A"+backspace+"B" so you can see it cycle through.
May be able to record macros with the T9 layer because the "KC_*"s are only sent at the end. Trying to do a macro with T9NOISY would probably fill up the buffer in just a few characters.