"you haven't disputed the initital point in PUB 550"

What makes you think I intend to?

Since you are using the word "contractor," is there a contract? You can't claim a formal arrangement for some purchase existed, and also point out it was all loosey-goosey with no formal recourse. Submitting for personal vacation losses through the IRS is sort of like submitting a taxable loss for a love scam: "But she took my money and then didn't come see me!"

Is this in a regulated location, like Montana (we have outfitter licensing) or Alaska? That would give him some contact points. You point out that others have been on these trips. That's how social networking can be used to find out more options. Your client likely isn't the only one stiffed.