The sensor module is a lot smaller than pretty much everything in the link, except the Vivoteks - it's only a bit smaller than those :)
The housing is a length of 3/4" aluminum tubing with the "front" end tapered inward a bit to make the look cleaner. The back end is cut on about a 65-degree angle, just long enough to clear the back of the cable gland. There's an elongated slot for a mounting screw, and then we drilled and tapped a hole in the corner of the umbrella support for that to thread into, and added a set screw to adjust the tilt. The sensor module is locked into the tube with another set screw. Sorry I don't have any other pics that show the design better... overall it's probably no more than 2-1/2" to the end of the taper - really, about as small as we could make it to completely enclose the sensor unit.
At the time, it was the only HD camera we could find in the size and form factor we needed... oddly, it was probably less than 6 months after we made these that Axis released the M2014-E... with pretty much the same specs (81-degree FOV, 720p, color-only). Coincidence??