I had 14" Wild Ones on my '04 Road King. Very comfortable, but could have been taller.
I rode my buddy's '09 Road King with 16" Wild Ones today. I wouldn't want any lower bars than that. They look and feel good.
That said, I think the 12.5" bars on my SG are just the right height with a fairing.
It's amazing how similar in height all three bars are in relation to the seat, even though the measurements vary so much.