I may have a tweak, but I don't know if its gonna work. I was looking into it as well. My setup is just slightly different with a fat imac instead of an MBA. My managed libary is on the mini and I connect to it via GBit-Lan, no issues with that so far.
...I would install Aperture on the mini as well, let it point to the usually connected to the imac lib. Of course, no double connection at that time. Then I point iTunes to the Aperture lib, quit Aperture on the Mini and work as usual. iTunes on the always on Mini would just go for previews and hopefully not messing around with the database itself. I would always have my pics on the ATV and in sync with my current iMac, although the lib itself is on the Mini.
Anybody wants to try?
Had a thought when I woke up this morning - I wondered if the Vault was simply a copy of the Library. So I looked into the package contents and turns out it looks like it's pretty much the same thing. If that were the case, then surely I could just mount the Vault as the library for Apple TV to get access to!? ... is what I thought.
To confirm, I used a command-line tool called 'diff' to compare. And I found each file to be different from the vault. Very strange, so I created a thread for that in the aperture forum - https://discussions.apple.com/thread/4471883. Once I have the differences cleared up, I'll see if this approach will work. To be continued.