I've seen a lot of scripted files in the past that allow for a character to change clothing, locations (backgrounds), warp in or out, etc.
These were all customized scripts and as such are not readily available to the masses.
While there are MANY varieties of skins or GUI windows, most all can be resized and some are made for tall (full body) characters while others practically take up the whole screen.
Perhaps Robert thought it better to be able to resize the character with the drag of a mouse instead of an expanding window feature.