Five Ancestor Fist uses a form of Sanchin (called Sam Chien in Chinese), but they did not create Sanchin. Five Ancestor Fist dates back to the late 1800s and its creator was a contemporary of Kanryo Higashionna (the teacher of Goju Ryu's founder).
Here is a list of available videos:
I have the first one. Their Sanchin is in many ways similar to the way Goju practices Sanchin.
And there is also a book available by Alexander Co, the same person who made the videos:
http://www.amazon.com/gp/product/080483 ... e&n=283155
In the book and some magazine articles Co and another Five Ancestor stylist have tried to make the claim that Five Ancestor Fist is the parent of all Okinawan karate, Goju Ryu and Uechi Ryu in particular. While Five Ancestor definitely seems related to Goju and Uechi, to the same extent as Goju and Uechi are related to each other, it is doubtful as the parent of either. It is more likely that the 3 are sister styles with similar influences.