Posting in the Magento forums has been disabled pending the implementation of a new and improved forum solution which should better serve the community.
For new questions please post at magento.stackexchange.com, the community-run support site for the Magento community. We will be providing updates on the new forum solution soon. For questions or concerns please email email@example.com.
I’ve had clients who wanted this before as well. My solution was simply to add a category called ‘brown’ or ‘red.’ This works, but makes for more maintinence as you must add or remove it to or from both places.
What I would really like is if you could add attributes with little icons or thumbnails to the dropdown! But that’s for another post.