I have giant hands. Large gloves are tight on me and I have to use the largest size they have. For reference, from the base of my wrist, where the Radius and Ulna meet the Carpal bones to the tip of my middle finger is just shy of 10". On my Logitech G15 keyboard I can reach, one handed, from the G keys to the ";" key without trying to stretch too hard. I've only met two people in my life with hands larger than mine; one was a linebacker and one was a welder.
This is an interesting thread seeing how I work for hand surgeons. It is a nice change of pace to see pictures of hands outside of a medical setting.
Here is a picture