The 120Hz would be so I can slow it down 4x for slow-motion shots. Pretty specific need but it looks cool!
Hmm raid could work; actually, Dxtory has a feature where it can split the file between two hard drives/SSDs while recording, so they might not even need to be raid-ed. I've tried it with my current setup and it struggled, as did the M4 on its own, but I'm sure there's a way!
Yeah expensive :/ Needed an upgrade anyway though, determined to run PS2 on max settings
I got quite lucky though, I got a fellowship to do an MSc in Statistics over 2 years while working and it pays quite well (for a first job at least) - figured I'd blow some on this!