No I haven't, but I know several people who have. They are way more experience than I am and were very impressed by the whole thing.
Much better than you'd imagine it being possible over the internet.
In theory, you can go all the way to black belt online - yes, they will even grade you online - just tape yourself going through the techniques in the corriculum for each belt, and based on your performance you eiter pass or fail
It's quite briliant actually