Matthew,
I know this is an old thread, but you’re flat wrong about almost everything you said. Firstly, 24fps cDNG from the Blackmagic Cinema cam is around 120 MB/s. I have single spinning hard disks that can hit that read target, but a two-drive RAID0 array would more than do the trick. How much is that, you ask? A 3TB drive can be had for around $100. You do the math.
Second, debayer is computationally expensive, but if my two-year-old midrange laptop can do it faster than realtime, I don’t think it’s an issue.