For what its worth, my 110 came with a bonnet mounted spare, but I found that it restricted my vision when offroad. I purchased a Mantec rear carrier and appreciate getting the tire out of my vision and it is a bit easier to wrangle than when it was on the bonnet. I also like being able to fully open the bonnet when working on the engine, something not possible with the tire there.
I think that with the Mantec I will be able to run a canvas top with a half side hinge rear door. All of the mountings are on the lower 'half' of the truck bed.
On the roof...may be easy now, but what about in 10 years. : )
I find that the tires on my truck get heavier as I get closer to 60!