I've considered many off-the-shelf solutions, but my primary goal is one of creating a secure shared storage pool that is armored against
bit rot, and that means going with something based on ZFS or btrfs. And since btrfs isn't officially released yet, that means ZFS. I have already constructed two external RAID1 boxes we pass around that are each 2x2TB, one for Mac and one for Windows, and those serve adequately for offline backup, but they are a) normally offline/inaccessible/inconvenient and b) RAID1 is still susceptible to bit rot. Hence my longing for a large, server-grade NAS.
As for the time limitation, my situation is more one of not having contiguous time. Assembling a computer is not something that has to be done all in one go, and I have built many computers one piece at a time as time and wallet permit, so that is nothing new. Also, if I can finally shed my house soon, a project such as this may actually become plausible.
--Patrick