Edit: My last post was more of a hinderance than a help, so i took it out.
In my last post I discussed a possible way of doing animation pivots – it sadly was just notes in my book and spare of the moment ideas. I think i missed out a vital chunk, and i think in theory I can make it a little cleaner – weak referencing not needed.
So this is still theoretical, but if we examine a standard object matrix3 transform it contains the transform space and its pivot space i.e the offset to keep it in the right position. So if we essentially generalize this idea (i.e making itself over the top of itself) i think we can work it out.
Charles Looker 
You can fake animated pivots easily without going through all these hassles.
Yes you can fake them using xform modifiers etc.. but this can cause the issue of drift – understanding transform matrices and the underlying object-offset ideas in max will give you a lot of power.