The now defunct Odyssey Automotive Specialty Vehicles often used Whelen Traffic Advisor housings cut down to 4 heads in the grill. Since these housing took 52/500 "slide in style" heads any combo of halogen or strobe (and later LEDs near the end) was possible. They were remotely powered, usually incorporated with the rest of the system on that vehicle. I know they were made in-house by Odyssey, but I don't know how they ordered from Whelen. They may have had enough volume that they just ordered the 8 head housings, they might have ordered "bulk length" housings, or they may have ordered the housings already cut. What I do know is these were specific to that vehicle upfitting company. Whelen offered six and eight head versions of the oval style traffic advisor which were metal housings, and they offered one, two, and three head versions of the oval housing dashmiser, which was sometimes a plastic housing depending on certain variables and time frames.
Whether or not to his example should be considered "factory" or not is less interesting and important to me than the fact that it represents an interesting application from a specific manufacturer of a vehicle type. I really liked the idea of using the oval housing on a push bumper, I thought it cleaned up the install very nicely. I have since used dominators on push bars basically stealing the idea and I been very happy with the look.