I was checking out the Wikipedia site for Sinxay (which we created with the help of an Elance freelancer, Daniel, from Italy) and see that someone added a French edition of Sinxay under the heading Further Reading. That’s the neat thing about Wikipedia, people who are knowledgeable can add information to a site.
When Maha Sila Viravong was working on his analysis of Sang Sinxay from 1952-1969, he read multiple palm-leaf manuscripts, including one brought to Vientiane by his colleague, Nuay Abhay, from Kong Island at the southern tip of Laos. Maha Sila considered this the most complete version, and finally published the first complete poetic version of Sang Sinxay in 1969, now known as the Golden edition of Sang Sinxay. We have an English translation of Nhouy Abhay’s, Sinsay: chef-d’oeuvre de la littérature Lao, which is quite abridged, compared to Maha Sila’s Sang Sinxay.
Sinsay : chef-d’oeuvre de la littérature Lao
Author: Pāngkham.; P S Nginn; Thao Nhouy Abhay.
Publisher: Bangkok : Tiew-chuy Sae Tiew, 2508 
Edition/Format: Print book : French
– via www.worldcat.org