Yes, something like this could work. I was trying to think of something that did not include datasource applies-to-partitioning since I find that to be a source of serious headache -- difficult to maintain, difficult to know what applies to what without deep diving, and due to lack of inheritance it is too easy to create semantic divergence where there should not be any. You are probably right that this is all I will be able to do at this time, was just trying to think of a method that didn't further encourage that methodology.
Thanks,
Mark