there was a little french dude that was pretty good at it a few years back
not a big rider or anything but he had the ability to switch foot all the time
and from what I remember he said back in the day, he just learn riding that way so he didn't had a weak foot at all
here's a vid of him
he's the dude on the 20"
http://www.dailymotion.com/video/x4hhe2_mini-video_sport
as I said, don't be harsh on the riding, he was young and still learning