Sounds like i should take a gander at FreeNAS, that would possibly do the trick.
Tis purely or a file server for a very small 3 person business.
FreeNas will do it with capacity to spare
I boot it from a 32mb usb 1.1 key
Runs samba, nfs, iscsi, ftp, http, integrates with Active Directory
. Can do raid and all sorts of goodies.
Wish they made plugins for it though, if it could be a print server Id be running it all the time.