Eventually I want to be able to associate every object with every other object in the system...
Dirk, your solution of adding an attribute to acs_objects will not allow you to do this, at most you will be able to associate an object with one other object, and the association will be of an unknown type (or a single type). Or maybe you can explain how it will work.
Also, repeating data in a parent table (acs_objects) is denormalizing in the wrong direction isn't it?