I sleep in the KJ all the time, and I'm 5'10" - oh wait, you said the back!!!!
Like I said, I can pull off a nap while the wife drives quite easily (sometimes it's better that way

) but to try sleeping in the back would be a whole new adventure I'm not ready to try at my age.
We have an '06, and from what I understand the '05s on where the first ones that the back seats actually fold down close to flat. Even then, I bet I'm looking at curling up like a kitten... I suppose maybe with an air matress, and if I could get the jeep level enough...
Not to highjack the thread, but has anyone tried the "tent-on-the-roof" type outfits like ARB sells? Just courious.