Jeff - My solution will deviate a bit from what others have suggested.  It very much depends on your intended use.  I originally kept my Mach 1 head in a Pelican 1610 rolling case because I needed the rolling features for star parties and I wanted to keep more of the associated parts (hand controller, etc.) in a single case.  Then there came a time when lifting that heavy Pelican case in and out of the SUV became a headache (or technically a backache).  So my current solution is lighter, and might be the smallest hard case that fits the Mach 1 head plus the counterweight shaft - the Nanuk 940.  Significantly lighter and smaller than the Pelican 1610.  I pad the few open spaces with air bags and heavy-duty bubble wrap.  I have found that my back is much happier with multiple smaller cases than one big heavy case.  Remembering to bring the multiple smaller cases is not too hard, as I keep them all stacked on top of each other.

Npte that I am assuming the Mach 2 is essentially the same dimensions as the Mach 1, and that I would also use a Pelican case like the 1610 if the mount were traveling via airline checked baggage.