Have you checked out the classifieds here on Crappie.com. I would think for the price under $1,000 you can have this Humminbird 999 SI HD unit comes with both transom and trolling motor transducers. Just my

http://www.crappie.com/crappie/perso...tm-hd-xducers/

http://www.humminbird.com/Products/999ci-HD-SI-Combo/