I have the same cosplay outfit. I lived in Alaska at the time and I rigged up a Victorian style jacket, white dyed pink, for when I was outside. I don't have it with me but it worked well. It was before I came out though, so I wasn't using it to hide my chest, just as an accent. You could also try a shawl, which depending on if you are buying the outfit or making it yourself it might go well with it.
CursedFireDean: there is an issue where he dresses in a pink ball gown. I can't remember the context though, I haven't read manga in years.