Thank you for your comment and for visiting NCpedia! I searched NCpedia and found that there are two articles that mention an Ethelred Ruffin: https://www.ncpedia.org/gsearch?query=%22ethelred+ruffin%22. You might want to check out those articles and their bibliographies for more information.
So far, I have not found any connection between him and the NC Constitution. If there is anything specific we can help you find or you have any further questions, feel free to reply to this e-mail or contact us: https://statelibrary.ncdcr.gov/contact-us.
Taylor Thompson, Governmenr & Heritage Library