Whats appealing with the Mac Pro's is the form factor, it's literally sackable in your carry-on luggage and you'll stay under weight. The thought of sending this stuff tumbling down conveyer belts is terrifying.
Pelican cases are pretty indestructable and utilitarian. I've always packed most everything in them with no regrets and 100's of flights. That said, I always carry the laptop onboard in this:
http://www.pelican-case.com/1470-tan.html
then I can even put it under some seats, or overhead, work on stuff as long as the battery holds out (not long). If I had to check it for some stupid reason I would have good faith in it. IN fact, I used it as a packing box when it needed to be shipped for repairs.