DCBennett,
What does your sales rep have to say about this? Or customer care? Or anybody at Dell? Their support of poweredge machines is generally FAR better than this, and I'm extremely curious as to why they haven't made this right.
At this point, replacing the hardware entirely is cheaper than the downtime you've already suffered--and can expect to suffer in the future, given you history of chronic problems. If I were having your problems, there is no doubt in my mind that my rep would make good--and I'm not a large customer by any stretch of the imagination. I'd expect a gratis replacement of these machines with something that actually works. If not, well, there are plenty of other server vendors out there!