It's no secret an all-new Ford F-150 will be coming out soon, likely solidifying the company's dominance of the 1/2-ton segment. But it seems developments for the Super Duty line are not being neglected, either. Ford has already announced some substantial engine updates for the 2015 Super Duty's 6.7-liter diesel engine. But that may not be the end of the story. We caught these strange-looking Ford F-750 prototypes testing around Dearborn.

There's about a 16-inch gap betweent the cab and the bed, and what looks to be either an auxiliary fuel tank or battery pack in between. There appears to be two auxiliary fuel tanks in the bed as well, suggesting this prototype is intended for high-mile, non-stop testing. We know it's a diesel due to the blue-capped DEF tank ahead of the side-saddle fuel tank on the side. This truck also has an unusual tacked-on front hood extension. The F-750 is offered exclusively (and ironically) with the Cummins 6.7 ISB, a version of the same engine offered in the Ram 2500 and 3500 HD trucks, in power and torque ratings from 200 hp and 520 lb-ft, up to 360 hp and 800 lb-ft.

Another intriguing possibility is that the tank between the bed and cab could be for a hydraulic hybrid system, something that has been in development and talked about for quite a while in the commercial truck realm. Eaton recently discontinued its Hydraulic Launch Assist system for commercial and medium-duty applications, but other companies are continuing development on their systems, such as Parker's RunWise system. Whether a hydraulic hybrid system will be offered on the next-generation of Super Duty trucks remains to be seen, but the systems have shown significant energy-recovery and fuel-savings benefits in testing.