User blog comment:ZoshiX/Project FBCraft/@comment-1713909-20140623180754/@comment-1917722-20140623184200

They are rendered larger anyway, just like the default block textures (however, there are texturepacks with higher resolution). Now if they would allow skins to have a higher resolution, that would be great. Having a default-res skin in a 64x64 texturepack is really weird at times.

Also, these are universal 32x64 skins, but 1.8 will have 64x64 as default sizewhich also means you can chuck a second layer onto the skin anywhere. I don't have my own skin at hand, but the MC wiki provides some good help.