all that said, the jeep does lose a lot of creature comforts like the rear AC you mentioned. the 2012 plus AC units are much more powerful than previous, but its hard to keep up with the amount of volume inside the vehicle with only 4 vents and a smaller fan. the dash is only a foot deep.
there are ways around all that though. a white hardtop with an aftermarket insulated head liner will run significantly cooler inside than the standard black and without the liner would. AEV also produces a cool roof rack that might fit your bill, there are also other options available from companies like Gobi and Baja
my jeep on 37's can grab 20mpg on the interstate unloaded at 70mph. loaded up with a hardtop gear and a passenger though a solid 17-17.5 is doable and expected.
As for the painted top... after sleeping in the back twice, I regretted not getting the matching silver top. Fortunately I live in the north so the heat isn't really an issue (I usually have the top and doors off when it's that warm!!). As for comfort... I don't have a lot to compare it to... but I've done several 3000m + trips in my JKs (07 and 2012) and don't have an issue with the comfort... Either that or I'm not picky enough?
As for the mileage... my stock JK (2012, auto, 4.10s) got 19.9 MPG once at highway speeds (twisty road, was babying it). I got 22 MPG once, but never went about 80 kph - so I don't really count that. I regularly would get 18-19 on the highway when stock - and this is only going 60. After swapping out the tires (33s) and a new front and rear bumper, I'm down to about 17 MPG on the highway.