Quotes Uncovered: Finally, the Whole Nine Yards

Each week, I’ve been inviting readers to submit quotations for which they want me to try to trace the origin, using The Yale Book of Quotations and my own research.
Today I will give my long-awaited response to the many questions about the leading phraseological enigma of our time, namely the origin of the phrase “the whole nine yards.” I am sorry to disappoint by having no definitive answer, but the reality is that many of the major etymological riddles have no known answer.
“The whole nine yards” is a commonly used expression denoting “everything possible.” Popular theories as to what “nine yards” originally referred to are legion. Ben Zimmer, in an excellent article on the Visual Thesaurus website, enumerates the following conjectures:

Capacity of a ready-made concrete truck, coal truck, or garbage truck (cubic yards);
amount of cloth needed for a Scottish kilt, burial shroud, or three-piece suit;
length of some piece of World War II military equipment (bomb rack, ammunition belt, etc.);
yardage in American football;
other types of “yards”: properties on a city block, naval shipyards, yardarms on a sailing ship, etc.

The first three of these in particular have many passionate adherents, although all are lacking in documentation and have holes in their explanations; ammunition, for example, is measured by rounds rather than length.
Scientific study of TWNY began with the Oxford English Dictionary, which traced its usage back to 1970. J. E. Lighter‘s Historical Dictionary of American Slang pushed the earliest dating back to 1967, citing The Doom Pussy, a book by Elaine Shepard about Vietnam War Air Force pilots. At that point all the earliest known citations were Air Force-related, pointing strongly to a military provenance. Then the database jockeys got into the act. A cadre of “antedaters” revealed a succession of older citations, reporting their discoveries on the Internet discussion list of the American Dialect Society.
First, Sam Clements used Newspaperarchive to unearth a story about NASA slang in the San Antonio Express and News, April 18, 1964, including this tidbit: “‘Give ’em the whole nine yards’ means an item-by-item report on any project.” Given the close nexus between the Air Force and NASA, the sentence seemed to strengthen the Air Force theory.
Online lexicography marched on, however. Bonnie Taylor-Blake posted to the ADS list a Google Books-derived 1962 usage of nine yards that clearly seems to be the same idiom as whole nine yards:

“Your staff of testers cannot fairly and equitably appraise the Chevrolet Impala sedan, with all nine yards of goodies, against the Plymouth Savoy which has straight shift and none of the mechanical conveniences which are quite common now.” — Car Life, December 1962.

Finally, Stephen Goranson, also searching Google Books, came up with a slightly earlier passage in a short story by Robert E. Wegner:

“Then the dog would catch on and go ki-yi-yi-ing from one to the other of the shouting pyjama clad participants mad, mad, mad, the consequence of house, home, kids, respectability, status as a college professor and the whole nine yards, as a brush salesman who came by the house was fond of saying, the whole damn nine yards.” — “Man on the Thresh-Hold,” Michigan’s Voices: A Literary Quarterly Magazine, Fall 1962.

All this state-of-the-art research has not so far gotten us to the etymological El Dorado of a definitive explanation. The two earliest examples are somewhat contradictory in their import: the Car Life one assumes that the reader readily understands the nine yards metaphor, while the Michigan’s Voices one introduces it as a cryptic catchphrase of a brush salesman. They do both seem to treat nine yards as the length of an extensive list (as does the third-oldest known occurrence).
Perhaps their main contribution is as negative evidence. Their context does not relate to the military, nor to the realms of cloth, concrete, or football. They are sufficiently removed from World War II to raise serious doubts about how a term from that war could have attained currency in the 1960’s yet left no trace of prior usage.
OK, people, go ahead now with the confident but unsubstantiated comments about World War II ammunition, Scottish kilts, and concrete trucks.
Also, do any readers have any other quotations whose origins they would like me to attempt to trace?