Slightly taller/larger tires on '05 F-250 4x4?

[Minnesota]

I need tires on my '05 F-250 4x4 and was thinking about going slightly larger than stock, which is 265/70x17. Not interested in 35s or such, just a little taller. I'm well aware of the power and economy-robbing quality of huge tires on our trucks but was wondering if anyone has experience w/ a particular size on stock rims on a non-lifted truck that they like.

I might be crazy but it seems to me that slightly taller tires would improve highway mileage by effectively lowering final drive ratio, (and dropping rpms at a given speed), as long as they don't increase rolling resistance too much like huge tires do. Plus I thought they might look good. TIA for any input.