That is definitely true, although I think the bigger factor is that the dimensions of all the expected JL variants need to be similar so they can all use the same assembly line.
As excited as I am for a Diesel Wrangler pick up, I expect that it will be a 2 door extended cab with a short bed and cost $4-5000 than a similar Pentastar equipped JL so probably not really and option for me for both reasons.
Hopefully gas mileage will be way up with an upgraded Pentastar, 8 speed transmission, and improved aerodynamics on all versions.
I also wish they would offer a totally stripped model with deleted carpet and sprayed in liner.
I can't see them only doing a 2door xtra cab truck. 4 doors is what the masses wants, whether it's a jeep or truck. In fact, I'd be surprised if they even offer a 2dr truck.