From the Japanese site青き猫耳帝国
(Aoki Nekomimi Teikoku) comes this short strip simply named "Gin-chan",
featuring a rather emo Suigintou. I suppose hanging around Megu
so much could have that kind of an effect.
One (so far) at the end is by the same author, but not a part of the
same 4-panel series. Thanks to Matt for pointing out the source.