I like the idea! It would be nicer if it was part of the OBS website like I think you mentioned earlier. But if they don't have the time to devote to it, and understandably so, then a separate site would be nice. It would also indirectly send traffic to their site anyway as people would be interested in going there to see more about where the cats have and do live.
Also, I think those of us on here that would really like to see it happen, just wanted the OBS' blessing so to speak. If you are going to put it together, I am sure many of us will help in any way we can, i.e. photos, videos, etc. I'd even donate some money if need be.