[boost] Singleton/Multiton

Currently, my dependency lifetimes, when set to use lazy creation, only create the object when the first pointer is created, instead of creating whenever the first dependency is created. I was thinking that it might make sense to extend this even further and have it only created the first time a member is accessed through the singleton. This would simply require one more intermediate pointer type. In addition, this intermediate pointer could function to lock the operations performed on the singleton/multiton. Are there any drawbacks to this plan, or should I implement it? -Jason