May I ask why? Any specific examples? I'm sure there are things I'm missing but, from my perspective, it wasn't worth doing if you couldn't have multiple attachments. Otherwise there is always that long shot of a collision which in my opinion, the vtable would be the last place I ever, ever, ever would look for a problem with a program. (Especially if I was using someone else's module and was not the author)
The only method it sets is one to decrement the attached reference.