If Google's web crawlers are correct, there will be a new Retina display 13-inch MacBook Pro announced today. The Apple Store is currently down, so we can't follow the link, but a Google search for "13-inch macbook pro" returns results at the official Apple site referring to the new model.
All we know right now is that prices range from $1200 to $2800, depending on configuration, for the 13-incher. That price could be old information, though, since the old, non-retina MBP started at $1200 as well. That price for a retina MacBook would be really surprising.
There's a small that this could be a false alarm due to an errant web tag on Apple's part—"RETINA MACBOOKS! Here are all the models, starting with the non-retina ones."—but a 13-inch retina model is something we've been expecting. There's also a chance it's on the books, but won't be announced today.
We'll let you know more as details come out, but for now, it looks like 13-inch retina displays! [Noah Robischon, thanks Mark!]