Any chance of expanding this to provide more flexibility like vray multisubtex?
Would be useful to have a default colour, and the ability to specify what IDs you want to use (as oppose to beginning at 1 in the corona multimaterial).
Then I can tell Corona to apply black (masked) or white (show) when an object has object g-buffer ID of 100.
I could make a switch using the vertex channel, or uvw xform offset but it would be much simpler to have the additional fucntionality inside a map and save the other methods for when doing something complicated.