I have a Synology LAS - a single bay DS118, 2.6L volume, 9W power consumption. Very very good model.
If you build one yourself - keep in mind, it will be larger, will take more time to configure, and consumer more power. But of course it is always more interesting to build something yourself, I totally understand this.
I recommend you to go with cheap low TDP Intel processors like Celerons. It is more than enough for this. Why do you need i7 3770 in NAS?
Some time ago, Chenbro produced very good chasis for NAS. Not sure for now. The main point - this is not a typical goal to make a 2-bay NAS chasis, because RAID 0/1 is not a best option. Typically professional systems use RAID5, which gives both good performance and redundancy
Chenbro ES30068 - 2 bay model
Chenbro ES34169 - 4 bay model
