Nintendo is a bit of a home body. It likes to keep its colorful list of characters on its own hardware and though it's announced the intention to develop some mobile titles in the near future, for the most part you aren't going to see Mario and friends on anything but a Wii U or 3DS for some time to come.
However if it did decide to license out that little red-hatted plumber, say to Epic Games or someone working with Unreal Engine 4 on the PC, this is what he might look like.
Developed by 3D artist Aryok Pinera, the video above shows Mario injected into many scenes made with Unreal Engine 4 assets. Programming was simple apparently, since it was made entirely with blueprints - an Unreal Engine system for drag and dropping pre-built code to speed along development.
Considering none of the assets are designed with Mario in mind, there are a few scenarios which look like they could come right out of the game.
Though admittedly the sound effects and accurate movements of the little guy do help you buy into it. He does run a little funny though.