I wouldn't make any movement on that particular feature without making sure you were in the loop. If it happens, I'd try to grab you for a chat on how your code can best fit into core or how core could best accommodate a module like yours to provide extra functionality that might not be needed in core (like a separate address book). Something like this wouldn't get into 2.0 given the dev. roadmap, though, so don't sweat being busy right now.