EDIT: I think Barney's comment did actually help me (although I may not have realized it at the time), to find a better way to handle the more traditional ORM in DataFaucet and I've since published a new version of DF (1.1 RC1) with a more traditional ORM tool that uses your objects from a Dependency Injection (DI) factory. The good news imo is that the new tool doesn't require any call-backs in CacheBox. Although I think this is still a valid question: are there cases in which we actually need call-backs from the cache service? Should they be implemented in CacheBox? I'm inclined to say no, but I'd still like to know what others think.