An Ifugao Packbasket from Northern Luzon, Philippines
In connection with ongoing research on work baskets in the Southwestern provinces of China, I spent some time during the Summer Institute in Museum Anthropology looking comparatively at packbaskets from societies in East and Southeast Asia. These baskets are from a variety of accessions in the ethnology collections of the Department of Anthropology, National Museum of Natural History, Smithsonian Institution.
Below, I share some photographs of a “backpack” basket from among the Ifugao people of Northern Luzon in the Philippines. Collected about 1977 and donated about 2001, it is catalog number E431417. Finely made, among its most distinctive features are the flaps that pull down over the opening when it is worn. Its a very clever design, one unlike any others among the baskets that I have seen in the NMNH collections.
Shreds and Patches 
What are the local antecedents for the pack? When working on the crawfish boats, I was very struck by the phenomenon of such seemingly “isolated” or “idiosyncratic” innovations that were picked up by one group but not by surrounding groups. The example that first brought this to my attention was the Chumash plank canoe (in California). I couldn’t get my hands on a lot of work at the time, but there appears to have been some subsequent work since: http://indigenousboats.blogspot.com/2013/01/the-chumash-and-tomol.html.
The dynamic (or possible dynamic) that you note is an interesting one. In the instance I touch on here, I know that I do not know enough to comment, as my survey is preliminary and based on a collection that is a very partial representation of a vast region. I have been struck, in contexts that have been more properly documented, how there are (as with western screwdrivers or chisels) a variety of forms and sizes of work baskets adapted to very specific applications. The best source I know for this in an Asian context is in A Basketmaker in Rural Japan https://archive.org/details/basketmakerinru00cort where there are specific packbaskets for specific loads as well as some villages having baskets adapted to, for instance, movement on constrained paths. It is fun learning new things.