This is hardly a unique case. I've heard of plenty of other problems with Sun boxes in the past, so I'm starting to think that their big claim to fame of "solid, scalable hardware" might just be a lot of fluff. At the very least it makes me wonder if you couldn't just accomplish the same thing with a cheapo Intel/AMD box.
Sun advocates will start chomping at the bit with stuff like hot-swappable CPU's, blah, blah. The thing is, you could probably just buy two cheapo systems (using one as a backup) every three years for what it costs to purchase a single Sun monster and pay for maintenance. If one cheapo system goes down, rely on the cheapo backup until it can be fixed or replaced completely. Using this approach you would probably still have plenty of cash to spare compared to the Sun strategy AND you have backup machine.
When I start my own company, I can tell you right now there aren't going to be any Sun boxes in it.