Here's where I've got to so far. At first I thought I would design one specially for the hanky but I was drawn to my Mary Konior books (as I so often am) and had a little look in there and found this edging which I thought would suit:
What do you think?
I had a moment of doubt wondering whether colours were right or whether a white edging would be more suitable... but I have to be honest and say that I don't really like working with white. I made the Iris edging in white not too long ago so if I can get away with colours, I always prefer working with colours.