How long does it take?

You need to do this in stages.

- take a supported board, make some change to it (change the print
messages!), do the full build/burn/test
- take a new board, but which is almost identical to a supported
board, do it again
- take a new board, with some new chip, do it again.

And then you're almost ready. And, you almost certainly still can't do
it if it's a new intel part, with ONE exception:
you can shoot for a board with an FSP-supported chipset, or you could
do the Quark, which would be truly wonderful to have.

Or you could go for an ARM board. Want to help with one?

Or an AMD board, which generally is far more friendly in the x86 world
than Intel at present.

ron