My thought is this. You don't want to appear to be drawing attention away from the real reason everyone is there -- to honor the deceased.

If the person you are honoring was into the Scottish community, regularly wore the kilt, etc., then by all means go kilted. It would be a way of honoring them.

But if they had no connection to this kind of thing, and you are going to be the only person there wearing the kilt, you need to ask yourself how much attention is this going to draw towards you.

In other words, is it going to be a distraction to others present?

This is an important consideration. To you, you may feel like you are honoring the deceased by wearing your nicest clothes. And I would agree with you. But will it be seen that way by other mourners?

Just remember, this day is not about you, and use your best judgement. And it never hurts to ask the departed's family members if they would approve. I'd put it in terms of you wishing to honor him/her by wearing your kilt, but wanting to make sure it would not be seen as out of place by the family. I'm sure they will appreciate you asking first.

Aye,
Matt