For the same reason, I repurposed my rear 8-ways to duplicate the functions of the S/T/T ones below. I went with 8 red LED's since my turn signals were already red, and I wired them all for tail lights (I want maximum possible visibility from the back). Since LED's draw very little power, I disconnected the 8-way wiring and tapped into the existing S/T/T wiring.
Some states, I think WI is one, will require the lights to be completely removed and the openings plated over. Some will be satisfied with painting over the lights and some don't care (as long as the 8-way function is disabled/removed and cannot be used.) The previous 55 watt (?) bulbs draw a lot of power and will have a pretty high intensity (about the same as your high-beams), which may be a bit blinding at night to other drivers.