A pair of recent General Motors patent filings show potential extendable cargo bed systems for pickup trucks.

Such a feature could give drivers the cargo capacity of a long bed when they need it, while maintaining the smaller footprint of a short-bed pickup the rest of the time.

One application, titled “Pickup Truck Cargo Bed Extension Systems,” was published by the United States Patent and Trademark Office (USPTO) on March 12. In this application, GM describes an extendable tailgate that could create up to an 8-foot-long cargo area.

For the design, the tailgate and floor would slide back to elongate the cargo area, with an option for hinged panels that can completely enclose the area between the tailgate and the cargo-bed walls.

On Feb. 27, USPTO also published a GM patent application titled “Truck Having a Dynamically Adjustable Box.” In this version, the bed is split into upper and lower sections, with the lower section mounted to the truck’s chassis and the upper section able to extend to create a larger cargo box. The rear bumper could also be attached to the upper bed as well.

GM isn’t the only automaker working on this idea. Ford has filed multiple patent applications for extendable beds, exploring ideas like a slide-out bed floor, an inner cargo box that telescopes outward, and a version with built-in steps and ramps.

So with GM and Ford already locked in a tailgate war that has seen both automakers develop elaborate multifunction tailgates for their latest full-size pickups, perhaps extendable beds will be the next stage of the Detroit automakers’ pickup rivalry.