This is the best YouTube vid that we've stumbled across in ages.
It's the handy work of gaming sound guru Jake "virt" Kaufman, whose real work includes Red Faction Guerrilla, Batman: The Brave and the Bold and Contra 4.
The "nextgen AAA" sounds certainly give Super Mario Bros a realistic edge that the 80s original never had, although his Italian accent needs some work.
Kaufman also has a show-reel of other retro classics on his YouTube page, including a quite brilliant Tetris re-imagining.
Check it out...