When travelling I rented 2 klx 250s from Zuela guesthouse. Seems they offer a service where you can drop the bike in southern laos - would make for a great trip with no backtracking.
https://www.google.com/url?sa=t&source=web&rct=j&ei=nvVSVPTMOIHFmwXtroCoBQ&url=http://www.zuela.asia/&ved=0CDUQ_BcoATAI&usg=AFQjCNGWcvMAVuSaL4_87Ww4AegTuwPzhA
https://www.google.com/url?sa=t&source=web&rct=j&ei=nvVSVPTMOIHFmwXtroCoBQ&url=http://www.zuela.asia/&ved=0CDUQ_BcoATAI&usg=AFQjCNGWcvMAVuSaL4_87Ww4AegTuwPzhA