Not sure if it was a member or not, but four days ago I saw an older couple at my local Flying J truck stop parked in the RV lanes in an M109A3 at about 330am. The truck had a homebuilt hitch, and a more or less homebuilt pup trailer that sported a pickup truck sized drop-in camper, with mil tail lamps, and painted OD... pretty spiffy setup. As I was busy pumping fuel, they fired up, which is what caught my attention.... you always know the sound of a multifuel.
Anywho, they popped on their lights...including a yellow rotating bubble up top, and pulled off before I could walk over there to say hi.
Basically, my reason for sharing all these useless details is yes, it is possible to put a convoy light on the 109A3. Granted, they only had one on this particular truck, but it was mounted behind the cab, drivers side, in front of the box. The platform where the light was mounted, was at the same height as the box, so the lamp itself was the only thing extending above the box. Granted, you'd lose sight of it behind the truck if you got too close, but hopefully by then the car driver would realize the 15,000 pound monstrosity in front of them was only doing 50 instead of 85 like everybody else.
If you encounter low branches on a regular basis, I'd like the telescoping idea myself. I know I'd end up ripping them off within the first week.
.rTBK