I don't think even the retrofit guys would touch this since most of them use the stock lens. You'd be wasting a couple lights assuming you DIDN'T mess them up. One would have to be filled with filler, sculpted and then you'd have to vacuum form clear acrylic over it (after heating it up.) Just to make the lens. Then you'd have to rework all the lights and the chrome bits inside on a separate light to figure out how to arrange them followed by fiberglassing the inside in to something decent looking before painting/plating. After that you've probably wrecked your second set of lights. So you'll need a 3rd set to make your final version out of...
So in short it's never going to happen
It may be easier to just paint the side of the light the color of your car and then clear the whole lens.