Using Intel ATOM as OpenSolaris NAS engine

I  recently started searching for a power- and price-efficient engine for modest-sized NAS, running OpenSolaris (Nexenta) of course. The idea to go to Intel ATOM first comes from their high power efficiency (1-13W TDP). To really benefit from it, do not only take into account the power used by the CPU, but also the whole motherboard (you know, chipset and GPU [Graphic Processing Unit]). ATOM is supposed to dissipate so little heat that a fan might not be necessary, so most motherboards for ATOM ship with passive/fanless cooling.