PBBAs are doing backup wrong
Agree with seanjregan. PBBAs are ok to replace or augment tape, but they do not fundamentally change the broken backup process. You need to address the problem from end-to-end, not just at the target. And you really aren't helping recovery much if you stick with the file-based, streaming-data paradigm. There are better ways to do things.
I actually blogged about just this a few weeks ago: http://bit.ly/La7K8Y