Interesting article by William Dalrymple ("Homer in India") in this week's New Yorker about persistent survival of oral epic poetry among some regions and castes of India. Traveling bard-shamans, dedicated to and invoking the power of a particular Hindu god, memorize poems thousands of lines long, and perform them in all-night sessions which can last for days or weeks.
A few years before Milman Parry went to Yugoslavia, recorded hundreds of hours of surviving epic performances, and basically invented an entire scholarly discipline, American anthropologists were recording the myths and songs of Native Americans. Much of my own (unknown) 700+pp. poem, Forth of July, draws on that material, from the character of "Bluejay" & the stories he tells, to the "ring-structured" passages (centered on the Mississippi River and the Ojibwa culture of the upper midwest) in the two sequels to Stubborn Grew (Grassblade Light and July).
(As I may have mentioned on occasion, all of this unknown long poem is available in print, as well as in inexpensive downloadable pdf format. Disclaimer : I do not possess an MFA in Creative Writing, nor am I associated with any academic Writing Program. I am, furthermore, not affiliated with the "New York", "Language", "post-avant", "New American", or any other "school" of poetry.)