Contact Jerry Stelmok at Island Falls Canoe. He has all the original molds and can answer all of your questions. I have seen 17 and 16 foot canoes as well, and currently own an early 16 foot EM White. Its called a "Regular" model in one of the older cateloges.
Jerry Stelmok of Island Falls Canoe at http://www.islandfallscanoe.com/about-us.asp should be able to help you with any questions about the availability of plans since he owns the original forms as Chris mentioned. White produced three lengths of their Guide Special model as described in the page attached below from their 1921 catalog.