Hi Mike, yes I have one of these beauties:
http://www.stereoscopy.com/jasper/panorama-test.html
I bought it to try making cubic VR images as among other things I have a camera with a 90 degree horizontal field of view and low distortion (ideal).
It has click-stops in azimuth, and has extensive adjustments to accommodate any likely camera+lens combination. In particular you can slide the camera back to position the nodal point of the lens at the azimuth axis, so foreground objects close to the camera won't have parallax errors as the camera rotates. This is perhaps most important when doing interior shots, not so important outdoors unless you want to do cubic VR. I used it a little but have stopped making cubic VR lately as I think they are boring once the novelty wears off.
http://www.dpreview.com/galleries/73...lake-pukaki-nz
http://www.dpreview.com/galleries/73...lmain-panorama
BTW I don't really understand why some think its desirable to put the sensor at the azimuth axis, this is quite wrong and you will get a lot of parallax. You can prove this yourself with an object close to the camera - as you rotate the camera in azimuth it will appear to move laterally with respect to the more distant background. When the camera is moved back so the lens nodal point is over the azimuth axis, a foreground object will appear fixed against the background as the camera is rotated.
From a practical perspective though, my best panos have been stitched from handheld shots when I happened to be at the right place at the right time, with little or no planning. On the occasions I've set out to do some landscape panos with this head in recent years I've invariably been beaten by bad weather.