Yes, in future, you will be able to consume and render vector tiles local to an iOS app, either as raster tiles or directly to a vector context (e.g. OpenGL). This is in development.
It's less about sources like SVG or PNG and more about the open vector format that Mapbox will serve up-to-date OpenStreetMap data and later, other sources, for these sorts of uses.
To experiment with vector styling, check out the TileMill 2 preview. Stay tuned for more iOS-specific stuff.