You need both flag and lights for the extender? I thought flag is sufficient. How do you setup the lights? It's would be a pain that you have to connect/disconnect the wire to the break every time you use the extender.

Sec. 547.382. LIGHTING EQUIPMENT ON PROJECTING LOADS.

(a) A vehicle transporting a load that extends to the rear at least four feet beyond the bed or body of the vehicle shall display on the extreme end of the load at the times specified in Section 547.302(a):
(1) two red lamps visible at a distance of at least 500 feet from the rear;
(2) two red reflectors that indicate the maximum width and are visible at nighttime at all distances from 100 to 600 feet from the rear when directly in front of lawful lower beams of headlamps; and
(3) two red lamps, one on each side, that indicate the maximum overhang and are visible at a distance of at least 500 feet from the side.

(b) At all other times, a vehicle transporting a load that extends beyond the vehicle's sides or more than four feet beyond the vehicle's rear shall display red flags that:
(1) are at least 12 inches square;
(2) mark the extremities of the load; and
(3) are placed where a lamp is required by this section.

A detachable light rig is easy to make. If you don't already have a plug for trailer lights, you can buy a simple harness to splice into your system.