Probably a daft question, but how integral to the whole story does the colour need to be?
I just spent a couple of days at the seaside with my Ms Kiwi in MIL's old camper van, total peace and quiet, and we ended up brainstorming story ideas...every time, somewhere in the process of arriving at a good idea, I seemed to circle away from any relevance to the colour we'd started.
So, and I suspect I am answering my own question, I presume the colour needs to be of quite central significance to the plot/theme of the story?