Yes, no sense using a 1000W PSU with any normal system - plus it's unlikely that a 1kW PSU will fit in any small case. You'd be far better off with a 500 Watt or so unit from a top tier maker (since when is Coolermaster on anyone's short list of PSU makers) - OIC it's cheap and looks normal dimensions... As far as the mobo, it seems to be almost unobtainium per Froogle (only found one hit and that was in Australia). Is it justifiable in rational terms?
Now to the point of this thread. Is normal mid-tower size "small" by your definition? How's this - 7.9" x 17.3" x 19.4" (W x H x D) (Bezel Not Included)? Those are the dimensions of one of my favorite cases, the Rosewill R5600 series. Excellent prices right now (free ship on some) and could handle your proposed system just fine, but only available in US and Canada. In other countries, look for the same case under the Yeong Yang brand in the YY-5600 series. The Rosewill R6A series are also excellent cases which may be found in other countries (and here) under the HEC/Compucase brand in the 6A series, but these won't take the 10.5" long video cards while the 5600s can.
.bh.