On SEN's routeshop page it lists Lanzarote, Dalaman and Antalya as potential destinations. Surely they would not put that down if they didn't think it was possible? It just requires the right equipment and airline to do so.
I hope someone like Jet2 (who showed previous interest in using SEN) could start some sun routes. Also Monarch are closing their EMA base next March so they have spare aircraft available for 2015. SEN have registered to attend the World Routes event in Chicago coming up so hopefully some good news can come from that.