wow.com link
WoW Forums thread
Here are links to wow.com and the WoW forums. I think I originally saw it linked from the epic thread on RealID being implemented on the forums. I did a google search on 'wow realid addons' and got a lot of results including one with a gearscore/realid hoax screen grab.
I would hope the API would not allow anyone but the BlizzUI to access that information but you never know.