My 2004 Nissan Frontier has the 3rd brake light and cargo light above the rear window. Not sure if it would fit your needs, but check it out if you can find a pic of one. If not I can post one up when I get home this afternoon.
My next door neighbor has one.I think I will climb up in the bed this pm and measure his and see if will look good on my truck."Midnight Auto Supply"Is now open.Lol.BJ
"Midnight Auto Supply. Our parts are hotter than yours."
I've thought about a 3rd brake light too,either in the cab roof or in the top of the tailgate above the handle. I was thinking about using LEDs though.
Over the tailgate handle would be cool as well.I will wait to see what Gravity 5 comes up with on the roof mount as I really need the cargo lite part as much as I need the 3rd tail lite.BJ