If you are open to non-Clan tartans that might work very nicely for both funerals and also classy formal events you might consider the Black Shadow/Shadow Black tartan (all black but with different thread appearences so that it has a very subtle pattern in certain light) or the Black Isle (a nice basically black tartan with some subtle grey tones). I have a nice new Black Isle myself which is absolutely gorgeous but very classy looking (although it is a magnet for lint).

j