Is there a script to expose the code for UV sprite animation?

I want to be able to have each particle spawned use a random uv tile from a tiled particle texture. Also I want to be able to start a cycle through the tiles to start at a random point.

That would be nice to get at. Hope someone has the real answer. A work around would be to create multiple textures (same tiles, different order) and either swap them or create different particle systems using them.