If you think BMW design is going through a crazy patch right now, that’s nothing compared with what was happening in the early 2000s. Chris Bangle’s controversial flame surfacing design language won cars like the Z4 sports car and E60 5-series sedan as many haters as fans.

But, as the latest video from BMW Classic’s YouTube channel proves, there was some even wilder stuff going on behind the scenes.

The video opens with a shot of two cars never seen in public before, one of which is a 1996 7-series concept with a gigantic double-kidney grille like a cartoon rabbit’s teeth, suggesting the 4-series’ face has been a long time in the making.

We’ll have to wait until the next episode to learn about this 7-Series prototype

But that car’s for the next video – this film is all about the coupe parked next to it. Well, we’re calling it a coupe, but this fascinating two-door, two-plus-two is a crossover in the truest sense, marrying a coupe body and the chassis and ride height of an X5 SUV.

Related: This BMW X5 Makes The New 4-Series Look Like A Masterpiece

Those of you with long memories, or just a geeky obsession with BMW history might remember that BMW revealed something kind of similar way back in 2001 at the Detroit Auto Show. Called the X-Coupe, it was a small coupe built on the chassis of an X5 and powered by a 3.0-liter six-cylinder diesel engine. Though it never made production, the exterior design was effectively priming us for the Z4 sports car that appeared in 2002.

But the concept featured in this video was built in 2004, proving there was more to the X-Coupe than a Z4 tease. BMW was deadly serious about building a go-anywhere sports coupe.

The front end of the previously secret car looks pretty awkward with its oval kidneys and twin circular lamps set into a shapeless bumper. But things get more interesting as you move rearward. For one, the door mirrors contain spotlights – ideal for wannabe cops to play pranks on their buddies – and then at the rear of the coupe things get really inventive.

BMW’s design team created a multi adjustable rear window and drop-down trunk lid that would enable owners to fit outdoor gear like bikes inside. We don’t get to see the trunk do its magic on the video, but there are still images showing how it could have worked. Inside, the cabin is straight out of a Z4, but with the addition of a couple of small back seats.

There’s no explanation in the video as to why BMW decided not to bring the strange hybrid to market. But in 2007 the company released the X6, so we’re guessing it lost out to a more conventional five-door sporty crossover that didn’t need an origami trunk lid to accommodate a couple of bikes.

Do you think BMW should have put this coupe into production? Let us know in comments.