After Tesla (TSLA 2.33%) CEO Elon Musk's Oct.1 tweet about a launch event scheduled for this Thursday, speculation is building. What exactly could the electric-car maker unveil? All we know for sure is that it will show off something called "D" and "something else." Heading into the event, there are a few noteworthy theories developing about what the company could unveil.

Tesla CEO Elon Musk tweeted this image on Oct. 1, saying it was "about time to unveil the D and something else." The awkward wording, he said in a tweet a few minutes later, was not intended. Image source: Tesla Motors.

What could the D be?
In the teaser poster for the D unveiling, the outline of the Tesla vehicle peeking underneath the garage door looks identical to the Model S. This has led the interwebs to speculate that the D is probably not an entirely new Tesla model, but most likely a new version of the Model S. This speculation is supported by several other interesting tidbits.

Musk has said the company will eventually launch an all-wheel-drive version of the Model S, but that has not happened yet. A general consensus is building that we will finally see this version of the Model S on Thursday. In the all-electric world that Tesla lives in, the company refers to AWD as "dual motor." The company is achieving AWD with the upcoming Model X by putting motors on both the front and rear axles, and the same approach is expected for the AWD version of the Model S. Dual motor, of course, is also where Tesla might derive that "D," supporting speculation that the automaker could be about to introduce a higher-end version of the Model S.

Model S and prototype of Model X. Image source: Tesla Motors.

But has the surprise already been leaked? A photo has surfaced in the Tesla Motors Club forums from user Adelman, who cited "a friend" as the photographer of a "P85D." Tesla already has a P85, a high-end version of the Model S; the name represents "performance" and its larger 85 kWh battery. But a P85D would be new to the Model S lineup. If the photo is real, a dual-motor P85 is likely the D that Musk tweeted about.

A dual-motor version of the Model S would make business sense for the company. As a supply-limited company for which the main constraint is lithium-ion batteries, Tesla could boost its cash flow by introducing higher-end versions of the Model S with larger profit margins to take advantage of the excess demand as the company continues to expand to new markets.

Furthermore, a dual-motor version of the Model S could present a compelling value proposition to consumers willing to pay more for the best Tesla on the market -- and what is likely to be one of the best cars in the world. The instant responsiveness of electric motors, a separate motor at each axle, and the low center of gravity of a Model S (thanks to the battery built into the floor of the vehicle) together could make a dual-motor version of a Model S one of the best AWD vehicles ever made. The increased power from an additional motor would likely also make the already beastly fast car even more powerful.

What could "something else" be?
Bloomberg, citing a person "who asked not to be identified because the details aren't public," reported that the company will introduce semiautonomous driving features for its vehicles during the event.

"Tesla ... will make its first foray toward automated driving, joining luxury rivals in offering high-tech features including one that can keep the car in its lane," Bloomberg reported.

Citing Tesla spokesman Simon Sproule, the report also said the automaker actually started installing cameras in the Model S last month, "including a forward facing one behind the windshield." But as Tesla enthusiast and author of Owning Model S Nick J. Howe recently observed, it isn't clear yet whether these cameras are being installed in 100% of new vehicles or only in a limited number. There is "more news to come" on this topic, Sproule told Bloomberg.

Musk recently told CNNMoney that by next year Tesla will have a car that will be capable of driving autonomously for 90% of miles driven, and that the company will be a leader in pioneering self-driving technology.

Model S charging. Image source: Author.

Could there be any other surprises?
Tesla has two vehicles in its pipeline that we know about: the Model X, which is due for launch in early spring 2015, and its Model 3, a smaller sedan aimed at the mass market with an affordable $35,000 price point, due for launch in 2017. It's possible that either vehicle could be shown off during the event.

While Tesla has unveiled a prototype of the Model X, we've yet to see the official production version of the SUV. Nothing has been shown to date of the Model 3. But Tesla has said it will be slightly smaller than the Model S and have a range in excess of 200 miles.

The Thursday event could have meaningful implications for Tesla's underlying business. A dual-motor version of the Model S would provide upside to Tesla's near-term cash flow, and compelling semiautonomous driving features would enhance the value proposition for the company's vehicles.