What a simple solution.. I remember nearly doing this for my iPhoto library, but for some reason did not. I don't remember if there were sleep issues with the NAS (or specifically the hard drive I was using) to make me hesistate.
I am going to try this later today.
Since the storage is simply on the NAS, do you know if the Mac Mini will use up the same amount of resources streaming to the Apple TV? I'm assuming yes, since the NAS is just acting as storage, and iTunes on my Mac is still doing its own thing.
Luckily everything is hardwired on a gigabit router.
My iTunes library lives on a WD Network drive, it works well, but I do have to make sure the mini has the drive mounted by clicking on it first before launching iTunes.
in addition, Plex points to the same library to stream not thru iTunes.
Win+Win!!