Recording Video Directly to External Hard Drive

I work in a psychology lab where we record video of people for research purposes. The video feed used to record directly onto DVD and miniDV, but shortly before I arrived here, the DV deck broke. Instead of using scarce grant money to buy a new DV deck when that technology is rapidly becoming obsolete, I would like to find a way to record the video directly to a RAID, ideally in a format that is compatible with Final Cut Pro 7, as that is what I use to edit the videos.

The cameras are wired to an audio mixer and an a/v router which uses S-Video and RCA cables for the audio. We have two 4TB G RAID drives ready to go.

What additional equipment do I need to make this happen? Is there even such a thing?

Thanks in advance for all your help!

Dan