I sometimes see these as a post-modern version of the stories told from the perspective of a boot or a coin, which were a big literary fad during the 18th century. I think the best one is Joseph Addison's "Adventures of a Shilling", in which the hero-coin implicitly presents itself as a Peruvian slave and a wastrel heir becomes an abolitionist.
http://www.ourcivilisation.com/smartboard/shop/fowlerjh/chap4.htm
The genre has been given a really unfortunate name, the "it-narrative". There's an anthology of essays on the topic I haven't read.
http://books.google.com/books?id=QS035TUNxpwC
I don't really have the wit to present a proper materialist analysis of the whole thing, and I bet some genius has already done so in that anthology, but it's hard not to see Salt, Cod, Potato, and all the rest as a continuation of the same theme. Commodity as Zelig (or Forrest Gump).
Cheers
CWS