Peter Yu, developer of the wildly popular Narcissus transmog/wardrobe/UI add on, recently posted a fun little trick that allows you to use two macros to see what your character would look like if their hair did not vanish when they donned a hat.
Trivial, you say? No sir! I have long bemoaned the amazing collection of chapeaux that I cannot wear due to the automatic hair cut. I even went so far as to ask a developer about it one BlizzCon – perhaps you were there? Perhaps you saw the video?