Transformers artist extraordinaire Dan Khanna has posted some very cool artwork on his Deviant Art Account of the unreleased redecos of Transformers Energon Optimus Prime and Megatron. The three pieces of art show Optimus Prime in his normal form and his super mode, and Megatron in all his glory. These pieces of artwork would have been used for the Target Exclusive redecos of these leaders that would have also come with WST Optimus Prime and Soundwave, respectively.
If you like the artwork, then good news! There is a chance for you to own the linework (uncolored versions) of these one of a kind works of art. Check out the auctions on eBay over here for the two pieces showing Optimus Prime and here for the lineart for Megatron.