What's in dossier's dossier?

Nancy Friedman (at Away With Words) has posted some observations about Perrier's new campaign that plays with the water's familiar logo. Comparing the ads to an older (for Napier jewelry) ad she notes that while the jewelry slogan "Napier is Snakier" was a clue to pronunciation (they obviously rhyme right?) the Perrier ads probably don't intend the same. She writes (regarding the word 'manlier' incorporated into the logo): "I'm not certain Perrier actually wants us to say man-lee-AY, but maybe we can start something."

This reminded me of the recent Gallicism topic (scroll down or click here). For the record: If people start pronouncing common words like easier, funnier hungrier manlier angrier etc with the "-eeAY" ending I'll definitely agree with Mr Urdangs "pretentious crap" claim. "Oh...this brie is a little cheesi-ay than I like. I don't usually try foreign foods but I'm feeling a little risky-ay than usual."

So I started thinking about the -ier ending on words that are likely to be pronounced in English with the Gallic "ee-ay" ending. I came up with a list of several words and started comparing all listed pronunciations in all my dictionaries. Of course the etymology of the words is relevant so I started paying attention to those too. And I found a fun little disagreement. As etymologies will often reveal. The word in question: dossier

Sources consulted: OED, Merriam-Webster, American Heritage, Webster's New World, Webster's New Twentieth Century, Funk & Wagnalls, John Ayto's Dictionary of Word Origins, Online Etymology Dictionary

All sources agree that the word is French in origin, meaning a bundle or collection of papers, and those who push it further agree that the root goes back to dos: back < Latin dorsum.

The connection to back as identified by MW AHD WNW and Ayto is that the bundle of papers was labeled on the back (probably spine?).

The OED says of the bundles: "from their bulging [they] are likened to a back."

A nice online site, the Online Etymology Dictionary, is the only source I found that claims both possibilities, saying that the connection is "supposedly" to the label on the back, but "possibly" from the resemblance to a curved back.

Will we find conclusive answer to this?