www.pocketpcthai.com has landed some pictures that show the iPAQ h6300 next to the forthcoming hw6500. They show that the hw6500 is shorter than the h6300, mostly due to the lack of protruding antenna. Thickness and width seem very similar. The official specs on the h6300 are that it is 5.42 inches long, 2.94 inches wide and .82 inches thick. This compares to the leaked hw6500 specs of 4.5 inches long, 2.8 inches wide and 0.63 inches thick.
Image source: www.pocketpcthai.com