What area are you from and what are the prices you’re looking at? Frankly I’d say it’s a mistake to buy any 1366 machine for a new system unless you’re in an area with a very limited used market, especially using an old dual socket system as a NAS - it will unnecessarily increase your power costs with little return.
Redundant PSU is largely a moot point without also having at the very least two different circuits feeding them. ECC memory and dual NICs can be had on any other Xeon platform (as well as with some standard Intel Core systems).
You should read through the NAS Killer 4.0, Anniversary 2.0 SNAFU, and OTiS build pages for an idea of hardware recommendations and associated costs based on your use case.
Just NAS duties, NK4 will be cheap, low-power, and effective. NAS+Plex combo, OTiS for quicksync. Heavy compute, lots of VMs - SNAFU will get you the highest core count/performance for the cost without sucking as much power as a 1366 system.
If you must go for a prebuilt rackmount system, I have heard it on the grapevine that there may be some similar but newer systems available at a good price in the near future…