For Brick Red you need Mortar Gray!!! 
But, seriously, you could attempt to match one of the colors in the kilt as a contrast to the color of the hose, as others have suggested. However, you could also use a color that compliments both without necessarily matching, such as yellow. Ecru (off white or natural) or black, would also work well, in my opinion.
I have a pair of Brick Red hose myself and have worn different colors of flashes with them. My green flashes make them look, well... Christmas'y (maybe it's the color of green).
Nile
Simon Fraser fought as MacShimidh, a Highland chief… wrapped and belted in a plaid over the top of his linen shirt, like his ordinary kinsmen. He put a bonnet on his head, and stuck the Fraser emblem, a sprig of yew, in it. With the battle cry, A'Chaisteal Dhunaidh and the scream of the pipes, they charged to battle. "The Last Highlander" Sara Fraser
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