This is actually very similar to an issue I was having with my Mac Pro at the office - everything is working ok (or as good as 7 on a Mac gets), and midway through trying to build a scene, something simple as loading a material or adding a primitive kicks off the spinning beachball and then the entire system goes down - no control, can't force quit anything or switch apps. This is the only app that I've ever had take down OSX and require a forced restart which is a feat in and of itself, but it's only on that one machine, making me think it's a hardware conflict specific to that Mac.

That's great if this trick is working for you, but I can't imagine they would be compiling a non-universal version, though I guess they could have a botched installer or something... the same installers have been used on all of my machines and just the one has the big freeze problem.