A YouTube video showing a prototype of the Tesla Model X is a hopeful sign that things are moving in the right direction for this long-delayed all-electric crossover. Originally promised for late 2013, development of the Model X has been slower than anticipated, with Tesla currently claiming that cars will be delivered in the third quarter of 2015.

This Tesla Model X prototype was spotted near Tesla headquarters in Palo Alto, California, and looks to be more production-ready than previous Model X concept cars, with smaller wheels and tires and a bit more black cladding on the body. This seven-seat SUV shares its overall look with the Tesla Model S sedan, but has a higher profile and a more rounded greenhouse that should provide significantly more interior space.

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From the positioning of the door handles on this prototype, it looks like the Model X's innovative door design will make it to production. The crossover's rear doors open in a gullwing-style motion to provide a wider opening to the second- and third-row seats. The Tesla Model X is said to have a longer wheelbase than the Model S, will use the same under-floor battery pack design, and will come standard with the dual-motor all-wheel-drive system that's newly optional on Tesla's sedan.

Tesla says the Model X will be available with multiple battery capacity and electric motor output options. The Model S currently offers 60 or 85 kilowatt battery packs, with electric motor power outputs between 380 hp and 691 hp in the P85D model, so expect similar options in the Model X.

Reservations for the Tesla Model X are open now on Tesla's website, with a $5,000 deposit required for an estimated delivery date of early 2016 for new reservations. Until we find out more official information, click here to see the full YouTube video of the Model X prototype in California.