It is true that you can't drive the creation of particles with map, shader or noise yet. But there are two workarounds. You can either drive a polygon selection with map/shaders/noise and use that to restrict the emission, or you can emit evenly and instantly kill particles based on a map/shader/noise.
Here is an example. The shader field drives a vertex color tag which is then used to set the particle colors on emission. Particles are emitted into a first group where there color is checked. If the it is below a certain value the particle is killed right away, if not it is moved to a permanent group where it will happily continue it's particle life. In case you wondering where the animation is coming from, that's set in the Shader Field with the remapping graph to cycle through different grey values of the texture. This is not the most efficient way as the buffers need to be cleaned up more frequently than needed, but you can achieve the intended effect.
kill_by_map.c4d