I wouldnt consider it too flashy unless the tartan was brightly-based or was more than half of a bright colour.
By the way - do many of you go kilted to funerals? I have only been to a couple but I think it would be good if I could wear my kilt (Campbell Ancient - Black Watch Ancient) to funerals with a black Argyll, black hose, black ghillie brogues and black shirt (or white shirt with black tie) and not "stand out" as being "unacceptable". I would be honored if people attended my funeral kilted and I want to be buried kilted... although not for another 60+ years I hope!