Or better yet... would this work if i just spliced on some RCA jacks to a couple of strands of standard IDE ribbon cable?

I believe video signals need to be shielded or else they will have a lot of video-noise on the screen. So if you're going to do any splicing, it should be to the (I assume shielded) flat coax cable.

I'm not sure if there's even a real difference between coax cable and RCA cable for your particular application.