I did something similar last year. Market for mITX NAS boards is pretty bad. I went for ASRock N100DC-ITX – it has 2x SATA ports, but there's also PCIe 3 x4.
The main benefits of this board were:
* it's not from an obscure Chinese company
* integrated power supply – just plug in DC jack, and you're good to go
* passive cooling
Really hope they make an Intel N150 version.