For anyone else interested in scaling up pixel art, there are alternative methods to just using nearest neighbour, such as EPX or something. I found this article on Datagenics to be pretty solid:
It's linked to on that page, but here's a good paper on scaling/interpolating pixel art. They use a lot of SNES sprites as examples. Some of these are implemented in emulators so you can play around with them a little.
http://www.datagenetics.com/blog/december32013/index.html