No, there are no plans for MadWorld action figures. But if there were, surely they'd look a bit like this custom figure, whipped up by ebooze.
It's pretty much perfect. The angular sculpt matches the Wii's low-res textures, he comes with two chainsaws, and ebooze's paintjob gets the two-tone mix just right.
ebooze [deviantART, via Go Nintendo]