Ok, but one comment on it anyways: looking at it some more I think you could simplify it a lot by instead of having an array of all your states, have a single struct that holds all of them. Then you could have a stack of that struct instead an array of stacks, you could just use struct assignment rather than looping, and you could probably keep the type information you're losing by putting them all in an array.

Ah yes.. good idea.. I've looked at eberly's wildmagic 5 (the book is based on version 3) and he's gone away from this design.. he stores it in a VisualEffect class togheter with the shaders instead now..