Hi, i have a client that is thinking of buying for his restaurant:
4 Apple TV's, one will be connected to 3 Plasma TV's, another ATV to another 3 TV's, one to two, and one to one, in total: 4 ATV's to 9 Plasmas..
and each ATV will be connected to optical audio system..
and he want to sync all these ATV's to one iTunes library in one Mac Mini..
well, since the Plasmas will be outside his office, and he wont be able to see whats going on screen when using the infrared remote, he want to be able to see each Apple TV when controlling it from office, or use Apple Remote Desktop to control each Apple TV..

is it possible to do all that

You can use ARD to see what's going on on the ATV. But the picture is very choppy and you can hardly recognize anyting - at least for me ...

Frontrow on ARD doesn't refreshes, but with XBMC or Boxee it refreshes

so you think i should convince him to move from ATV towards MacMini??
though the Mini is more than twice the price as Apple TV!!!

You could use Panic - Transmit 3 - The next-generation Mac OS X FTP client! to synchronize the content on the AppleTV, but you would need to use XBMC or Boxee to control with ARD.