The mugen fits OK on the Asus P5Q Pro and it's not too hard to reach in to the push-pin connectors when the board is in the case. Picture below. Clearance over the northbridge is about 10mm, same for the heatsink at the back as it is at the same height as the NB (35mm height off the board).
A fan attached in the standard way to blow through to the rear case extractor hangs over the first bank of RAM so you would have to detach the fan to change RAM. Those with an upper extractor (like me) may be better served by installing the mugen the other way around and have the fan blow up and out the top.
