lets do some math
"The length of the nodachi's hilt varied between twelve to thirteen inches (30 to 33 centimeters). The blade was usually around four feet long" -wiki (cuz they are always right:p ; this means that hilt + the blade = the full length, or about 5 ft )
The average man in the world is about 5' "11 ish (all depends on which poll you use). The player models are actually about 4' 11" (if you determine by the about of skulls or heads they are tall). Here are some measurement (taken in fireworks):
sword 578 px
ironsnout 387 px
taking in account of persecutive and common error we will add 13px to the ironsnout and take 28 px from the sword (this leaves them to 400 and 550 respectively; it also makes it easier to calculate).
if the ironsnout is 5 foot (like i suggested), then the sword is about 7' 6", meaning that the sword according to wiki is about 2' to big. So generally speaking if you but the sword up end to end next to the model it would exceed one and one half of the ironsnouts, when it should be about 1 ironsnout (assuming that the ironsnout is about 5').
"ōdachi is apx. 65–70 inches long" -wiki
The other sword time listed is the ōdachi (or great sword) which is about 6' (6' is actually 72"; Note: this includes the blade and the hilt). NOTE: "they were found to be effective on horse back" - wiki
Point being that this sword is completely out of proportion and is not the correct size according to any standard :)
chasester
PS: for all you non Americans that use the metric system :p :
7' or 7 feet = 2.1336 meters
6 feet = 1.8288 meters
6" or 6 inches = 15.24 centimeters
px = pixels
Sources
Nodachi sword at wiki
Ōdachi sword at wiki