Check out this little thing.

It's effective cost is somewhere around £140 (£240 with £100 cashback at the moment)

4 bay NAS basically - can install any OS you like on it, 2 pcie slots, 5.25" bay incase you want extra gigabit ports. Freenas would suffice...

so thats a 4 bay NAS for £140... a decent 2 bay costs you that!!!