Oddly enough at my wedding much effort went into matching my kilt. The bridesmaids dresses and the ties & cummerbunds worn by the groomsmen were picked as they were a green that sort of went with my kilt. I even wore that bow tie, instead of my usual black.

No effort was made to match the hired piper, who was in his police uniform. But he was only there for the ceremony, not the reception. Some other family members were in tuxes also (I don't really get why) but they did not wear the green that the wedding party did.

I can see the cummerbund with the kilt as being something that breaks up the line, much like a belt does, but I don't like the way most of them are a satin like cloth and most kilts are not nearly as shiny. I think they would contrast each other too much in that regard. I did kind of like the cravat look, but to wear it properly requires to high a vest, and as such throws off the look.