After several hours Expedia found me two rooms at the JW Marriott in Miami. They are covering the difference (Marriott rooms are about $150/nite more expensive than the Hyatt), and they gave me a $100 voucher good for one year. All's well that ends well.
After four days of back and forth with Expedia, multiple calls, multiple hours on the phone and Expedia trying to book them in West Palm Beach, they were able to get Expedia to get them into a South Beach hotel (at the Hyatt rate) and a credit for a future Expedia booking. Good luck!
If you're interested reply to this message but that's an ungodly rate. It's at the Shore Club South Beach so it's probably really fancy.
Email me if you're interested and I'll share a corporate discount code.
something else on your own?
Given that Kayak and Expedia have nothing for close to this amount, see if they'll cover you for the price difference if you book one of the rooms ND has blocked at the Intercontinental Miami. That's $469/night.
But hurry -- the suites they had blocked are already booked.
If not, you might be without a paddle.