The sports bar is easily drilled so you can put a long bolt through, but you could also have someone weld a piece of (say) 4mm aluminium to the upper rear to mount the light on.
Electrics are another story. I would suggest that beneath the welded mount you drill a hole large enough for the wires and run them down through the bar to the tub that way. You can run cable out through the corner of the tub then along the chassis to the front (don't tap in to the power @ the rear, unless your work light is < 20W). If it's over 20W, run the cables to the front, use an appropriate fuse & relay to deliver power and all will be well.
