Maybe I'm an idiot, but I'm having trouble finding such things. Please point me in their direction.

As to lifespan of DVD±Rs, I don't really know, but it's the only vaguely cost-effective solution I've got. We're currently using them and we're going through a hundred or so a week. So that's, what, 450GB a week? What else am I really going to do? Bare IDE drives aren't near-line enough, not to mention being way more expensive. Backup tapes would be very expensive, not to mention the time it takes to deal with them (again, not near-line enough). If you have a better solution, let me know.