That is the male mesh wearing a shoe clothing layer for the additional height that provides.
However, I was recently taking a closer look at that in an attempt to create an as proportionate as possible giant avatar. Using more accurate prim measurements, rather than the scripted rulers I usually use for cursory looks, I found the maximum height of the SL avatar is actually 8'8"/263cm.
Without the shoe layer height, the male avatar mesh maxes out at 8'3"/251cm.
As for how successful I was in creating a proportionate giant?
|Avatars this size are more common than male avatars shorter than the yellow NBA figure in the middle.|
The avatar also had a short torso, even maxed out at 100 the torso was nearly half a foot too short for his body. This wouldn't have been so bad if the arms could be equally long respective to the legs to achieve that lanky, gangly look, like the giants of Skyrim.
Another odd thing, but maxing out the head size does allow for the giant to be almost exactly 8 heads tall, so there's really no excuse for all the pin-headed avatars.
Still, it's not something I'd feel comfortable slapping the "Vitruvian Shapes" moniker on and it really highlights the limitations of the appearance editor that while you can make a shape over eight and a half feet tall, you can't give it the proportions of a figure that tall.