Call me paranoid (this is about security after all), but there's no visual distinction between data and power-only cables. While a rogue employee can wreak all sorts of havoc in any data center, it's nice to have as many correct-by-inspection systems as possible.

I don't see why one couldn't get a power-only hub, but I couldn't find anything that appeared to be high quality in a quick search. I did find some pretty nice looking rack-mounted kit, but they all appear to be data hubs.