Aloha ! check out the late Herman Suwanda tape on Sarong techniques or his brother, Bambang Suwanda as he has a recent tape on it as well. Visit emaa.us for info
Also, my instructor has a vid available at http://asianfightingarts.com and there is a section of flexible weapons usage - not with a sarong but derived from the sarong work - on my Muncie Workshop 2004 vid available at my website at http://impactacademy.com Mike