Yes, it's finally here, from the Illy labs. Available for download at $9.95: http://dx.doi.org/10.1016/j.foodchem.2009.04.019
No, I haven't read it yet.

[Edit] Regrettably, the paper is entirely focused on the quality and persistence of crema.

I was able to download this through my library account

I have not read it yet, however, it appears to be a short (5 journal pages) though thorough analysis of the chemistry and sensory factors water quality brings into play in an espresso.

Thanks Marshall

Edit- Marshall - I do believe you are being overly harsh in stating the article is entirely focused on crema production. While I would not spend $10 to read it I do believe it has a useful review of the role of various ions on coffee extraction, water hardness and alkalinity with perhaps a (over)focus on bicarbonate and the effect of carbon dioxide on flavor and extration. I certainly learned a bit and did not find at least the review part of the article focused on foaming (crema). The "new data" presented was related to foaming/crema but for my education I found that secondary to the review.