Lol! I did a google search for the topic since it recently piqued my interest, and this thread popped up. What I was referencing was in Luna Eclipsed. Luna shifts her appearance to look like NMM then back again to appease a whim from Twilight to scare the ponies there. It's the only time I can think of where we are shown Luna shape shifting.
Btw...have another great year!