As far as I know there isn't one available commercially, but if you wanted to build one a good starting point would be a Gr8Tops Safari Cab hardtop.
This photo shows a Safari Cab with the roof unbolted and hanging above the Jeep:
How long is the roof on the Gr8Tops Sarari cab?
...I'm wondering if it's long enough for sleeping.
-Dan
I can't make out the sticker on the side, but this is the closest I could find.
Personally I would love a J180 style top for my 2 door.
I also like this:
https://www.youtube.com/watch?v=Hu2zahJOkuk