There are only three disk vendors now and I would assume that large customers buy from at least two of them. But knowing this information won't help you, because a new model from company X may be a dud even if the company's previous models were reliable. By the time any model has enough accumulated reliability data that you can tell whether it's reliable or not it's obsolete and you don't want to buy it.
This is the only publicly published information that's even slightly relevant (AFAIK): http://research.google.com/archive/disk_failures.pdf. It doesn't mention any manufacturers by name, but you should be able to draw some inferences from the paper.
I'm not sure that the information would be all that valuable anyway. Google's data-center environments, workloads and requirements are likely pretty different than your environment and requirements, so I'm not sure how the information would be useful?