Thanks all! First, http://www.flightmole.com/claim_recovery.htm is a recovery service I've come across, though I don't know that they're taking new claims at this time. Follow-up questions:

• I live in Arizona, so am I to understand that if I were to file a small claims complaint I would have to do so in NY?
• If I were to want the local authorities (in Venice?) to pursue my claim, how would I go about requesting this?

I have to say that it is very annoying the way Delta so brazenly ignored my requests for substantiation of their "opinion" that I'm not entitled to compensation, stating "any further correspondence would only be repetitive and unlikely to prove productive; therefore, we will not be responding to this matter again."

When I pointed out that the only reason our correspondence had been repetitive and unproductive is their unwillingness to address my question, an agent did reply stating they had "once again thoroughly reviewed" my claim and that "there is nothing more I can add. Please know we will not be responding to this matter again." And true to their word, I have not had another reply to my requests for further clarification. My latest email to them was two days ago after my phone call to them. In it, I listed the precedent case law, though not by name. I'll give them a few days more and then do as you advise and send them a notice that I plan on filing a claim. ... I'll also check to see if I have travel insurance through the amex card I used to pay for the flight. ... Thanks again for the advice!