ParaFUNalia
www.parafunalia.com in Gilford, across from the Mountain View Yacht Club probably rents kayaks. Do not know for sure, as they did do rentals at their former Meredith store.
Fay's Boatyard
www.faysboatyard.com in Gilford also probably rents kayaks, and Fay's has the Hobie kayaks which have foot pedals linked to a propeller device plus the standard kayak paddle.