Hi -I just had a case made that has a 10u section at the top and then a section at the bottom which has no rack ears, but a foam lined section which is MacPro sized. The case was much cheaper than any of the actual rackmount options that I could fine, and slightly more elegant I think! You have to be a bit careful spec-ing it to a maker, but I just had it so there are some bars at the back of the case to stop the mac sliding backwards, and the front door / lid has foam stuck to the inside to stop it sliding forward in transit.
Matt