Elon Musk left a lot of people wondering what, exactly, Tesla's upcoming "D" will be. Is it a brand new car? A self-driving vehicle? As it turns out, it may be something much more familiar-looking. Tesla Motors Club forum member Adelman has posted a photo of what looks like an unannounced Model S P85D -- that is, another high-end variant of Tesla's current luxury EV. It's not clear just what that suffix would mean, although most of the speculation points to an all-wheel drive, dual-motor upgrade borrowed from the soon-to-arrive Model X SUV. That could make the Model S quicker (or at least, better-suited to tough road conditions) than the already speedy P85 trim level you see on the road today. Whatever's under the hood, you'll likely know the full story in about a week.