I think you missunderstood the idea. A smart house system will be invariably an embedded system, and not a generic multi purpouse PC, which you all reply-ers immediatelly implied.
There is no need for USB mass storage drivers. It will probably have an own class ( USB-home-automation ) that can only do/read/write some sort of data. This kind of closes any type of attack vector based on making the system execute arbitrary code.
So I don't see the fuss with autoruns, or some obscure USB sound card buffer overrun - which was fixed the next day : this will not happen.
You make the mouse identify itself as a USB HUB with a mouse, keyboard and a flashdrive.
You make it simulate keypresses of Win+R, `F:\exploit.exe`, Enter (or Cmd+space, Terminal, `open /Volumes/pretendmouse/exploit`, etc.)
Anything you plug into USB can own your machine, and autorun is not even necessary.