Semi-official BMW tuner Alpina has given the world some fantastically tweaked cars over the years, the latest of which is the 600-horsepower B7 based on the 7-Series.

As you may have noticed, Alpina tends to step where BMW's own tuner, the M division, doesn't dare tread, and it looks like the next offering will be based on the X7.

Our latest spy shots show a prototype for an Alpina X7 being tested hard at the Nürburgring. Signature Alpina cues include the horizontal slats of the lower front fascia, plus the multi-spoke wheels.

Alpina's X7 will likely be badged an XB7 if it's powered by a gasoline engine, though if there's a diesel under the hood then you can expect the name to be XD7. Given the importance of the United States and China to Alpina, it's more than likely we're looking at a gas-powered model.

2019 BMW Alpina XD4

2019 BMW Alpina XD4

The B7 super sedan packs a 4.4-liter twin-turbocharged V-8 conservatively rated at 600 horsepower and 590 pound-feet of torque. It also features a sport exhaust, a reworked 8-speed automatic transmission, and track-tuned suspension. All of these features installed in the X7 would make for an impressive SUV, and don't forget Alpina offers tuned versions of the X3 and X4 overseas, so the company has some experience working on high-riding vehicles.

Right now the hottest X7 is the BMW X7 M50i. The M Performance model is powered by a 4.4-liter twin-turbocharged V-8 rated at 523 hp and 553 lb-ft. It needs just 4.5 seconds to hit 60 mph, so imagine what a 600-hp X7 will do.

We currently expect the XB7 to debut late this year ahead of a market launch in early 2020. Pricing will likely match or exceed the $142,695 you need to pay for the B7.

Note, Alpina is also known to be studying a tuned version of the recently revealed 8-Series Gran Coupe. It would essentially fill the void of Alpina's previous B6 Gran Coupe.