Not doing it ourselves but there are lots of both expensive and reasonably priced NAS solutions out there. Now the server should matter not to a large extent. All peers are pointed to the NAS no matter what.
This is why I like being small and running P2P with two decent towers in the office. If the new tower has a glitch (RAID 1 so less likely, but ya never know...) then we could always switch back to the old tower for a few days to keep us up and running. We also have at least one too many laptops now, so one dead laptop shouldn't kill us either. We now have 5 computers and 3 users between the two towers and the three laptops.
we too copy the entire AC folder each night to two different yet identical drives. One stays on site, locked in a fire and water proof safe that is locked in the drug cabinet while the other goes home in a laptop bag each and every night. Cheap and simple off-site back up...
