I'm thinking about making your mount... The pipe thing will work great, because I'll have it mounted for just a few months in one room before I move it to another, which will probably require a different hang height.
I'm suprised that you did not run the video wire thru the pipe down the the projector. You could run the power on the outside and provide some shielding effect. That mount looks like it is perfect for this, all you would have to do is cut out the plexiglass where the center of the pipe is, and if you ran the wires above the ceiling you would never see them... Or use wire channels.