Because I'm weird and suck at drawing anything beyond straight-on-sides of them, I decided to make clay models of the swords so I can draw them better. These are the first two in this: http://www.furaffinity.net/view/8210913/ . The Chaos sword measures just under 7 inches... and is facing the wrong way in this picture.

They're not quite scale size since the Chaos sword can be used as two handed while the Friendship sword is around the size of a smaller Wakizashi (http://en.wikipedia.org/wiki/Wakizashi) and each side, when separated, is meant to be held in one hand (yey dual wielding!)