I am considering a fully loaded 27" iMac versus a MBP+ACD combo for my office. My desk is a built in wall hutch deep enough for a CRT montitor but only 19.75" tall. I measure a 27" iMac without the stand at 17.75" high. So if I VESA mount it on an articulating arm it leaves 1" off the desk and 1" from the bottom of the upper hutch. Desk is 5' long and the iMac would be open on the sides and I would pull it out 12" from the back wall with the articulating mount and slightly tilt it giving maybe another 1/2" of vertical clearance. Is this enough space for air intake and heat dissipation out the top back slot?