I've based him pretty closely on the second picture in that wikipedia article, even though it looks a bit anachronistic to me - the pelisse-looking jacket thingy seems particularly odd, to my (admittedly untrained) eye. But whatever, it's a dashing image.
As usual, I see some things to touch-up now that I've photographed the thing.
And just for fun, a picture showing Ivan with his opposite number, Mikolaj Potocki. I think the difference in character between the two historical figures comes across rather nicely in their differing poses.