I think there are some tartans like "Ireland red" and "Ireland blue" you could do, or perhaps the (I think) rather nice "St. Patrick" tartan? Or perhaps the ones of the four provinces?

I also think that MacLaren would be a good addition, since it's the Boy Scout tartan. Perhaps also some BSA theme buckles, or sporrans? I'm a bit interested since I'm wrapping up my Eagle Scout requirements, and I'd like to do my Eagle Court ceremony in a kilt.