You DO realize that greaves were combined with another armor slot, so it's either with boots or chest pieces.
This is still very much up for debate. It definitely isn't with boots, because in the demo when the player is killing the wolves, you can see skin above where his boots end. And because if they are attached to boots, then you could never, ever have leg protection if you were wearing regular shoes. Or every NPC in the game would have greaves on at all times. So, logic and visuals dictate it isn't attached to boots.
If they are attached to chest pieces, beast races are STILL only one slot down, because that slot would be gone across the board. But they aren't attached to chest pieces because 1) the picture shows no greaves, and the nirnroot picture shows a foot-long tangle of roots, so clearly they are intent on showing every detail of every item; and 2) there are pictures of elven armor with more armor than what is shown on the armor in the menu, as well as the picture of the female character looking at Whiterun who is wearing greaves.