The alleged user guide of the upcoming C5 Ultra has been revealed and in it we get a minimal artist rendition of it that shows close zero side bezels on the device.
http://www.xperiablog.net/2015/07/26/xperia-c5-ultra-confirmed-as-snippets-of-user-guide-unveiled/
http://www.xperiablog.net/2015/07/26/xperia-c5-ultra-confirmed-as-snippets-of-user-guide-unveiled/