http://www.backyardpoultrymag.com/issues/5/5-3/marans_chickens_layers_of_chocolate_brown_eggs.html
OKay check these out and look at the Splash maran on this site. I looked at pics of Wheaton, Blue Wheaton and Splash. He really doesn't look like a Wheaton or Blue Wheaton at all. My vote would have to be for a Splash Maran roo. They don't all look exactly the same, if you look up pics of Splash Maran roos you will see there is variations in how much of each color a bird has. Like these to pics the Splashes seem to have quite a bit of copper on the wings and the one of the left has some in his chest. Anyway this is my vote for what your bird is.
Good luck,
Michelle