Not to ruffle any feathers but the larger wheel would change the performance in a different way with the DRP. Raising the Center of gravity and changing the way the wheel takes the load. In the current design the majority of the weight is taken by the wheel. raising the wheel connection would balance the load more evenly between between the user and the wheel. The opposite of what a user wants. Several factors play into it but at current most users feel less than 50% of the load with the DRP. Mule (the guy in the second video that I linked above) posted his pack weights over at Hammock Forums a couple days ago for a group hike, he weighed the full DRP with frame and all came to 40 pounds, then he connected the waist belt and weighed himself, he only gained 15 pounds. The lever action that is employed by keeping the load on the small wheel would change as you increase the wheel size. As you may see in the videos the lower part of the frame of the DRP is made to act as a drag skid should you cross any obstacle larger than the wheel can handle. This comes into play when stepping over and around large rocks, logs steps, or anything else that may get in the way when hiking. When Skidding the load is still counterbalanced off of the user and you do not feel the weight on your self.