This one-of-a-kind E36 features a cool and clever sliding roof panel that lets sunlight into the cabin while doubling as a tonneau cover.

While never mass-produced, a BMW pickup isn't entirely unheard of. We've seen several truck-shaped creations emerge out of Munich, including one based on the X7. German coachbuilder Karmann had a different idea: It pegged the 3 Series at the intersection of pickups and convertibles.

Unveiled in 1998, the Karmann K2 concept was based on the E36-generation 3 Series, though whether it started life as a coupe or as a Compact hatchback isn't clear. It looks just like the regular-production 3 Series from the tip of the front bumper to the base of the A-pillars. Beyond that, it loses the B-pillars and gets a taller roofline that hides one hell of a party trick: a cargo box that's surprisingly big considering the E36 bones.

High-resolution photos of the K2 are seemingly impossible to find, and BMW told us there's nothing about the car in its archives department. Karmann filed for bankruptcy in 2009 and closed the following year so it can't help us, either, but there are a handful of low-resolution press shots floating around the dark, dusty corners of the internet's car geek aisle that help us piece together a better idea of what we're looking at.

Out back, the K2 features 3 Series Compact-sourced lights, a tailgate that flips down, and a large glass panel designed either to be removed, or to slide under the roof. Opening the tailgate provides access to the bed, which is plastic-lined for those Home Depot runs. The body-colored roof panel slides down and slots above the bed to unlock unlimited headroom while doubling as a tonneau cover. It's cool and damn clever.

Interior pictures aren't available, and there's no word on what powers the K2. We're guessing it's a stock, E36-sourced drivetrain. And, had it been built, we're also guessing many would have ended up swapped with the 3.2-liter S52 straight-six from the E36 M3, because why wouldn't you?

That's a moot point. Nothing suggests that Karmann intended to turn the K2 concept into a production model, and there's no evidence that BMW ever manifested a real interest in adding this funky, segment-bending coupe to its lineup. While we don't have concrete numbers to back this up, we'd bet that making this design study a reality would have required an investment far too big to justify for such an odd, niche car. We just hope this one-off is still out there somewhere, tending to various odd jobs.