Problem with this is that any scaling, rotation or fading effects you throw into the library/engine will slow down performance significantly, unless you throw in some OpenGL, but then you're probably tossing away the simplicity factor. Sore truth is that these 3 effects are the product of 3D hardware acceleration for 2D games.

There is, I believe, a 2 times zoom function in the JEDI-SDL units. Written for fast drawing double the size of any image you need.