Man you might really have something there. According to wikipedia the largest timber ratteler ever recorded was 6'2''. I killed one a while back close to that. Check it out here. http://en.wikipedia.org/wiki/Crotalus_horridus
Look under the decription title and it gives you lengths.
where were you at, i see the post says henderson lake, i didn't know we had rattle snakes like that in this area, that is a huge snake even if you are only 4-1/2foot tall(lil bit reference lol)