$20 to Bally's guy. He had just started his shift, so I was hoping it would give him some incentive to sort out good chips for when I returned later (if he got bored). Getting a Mint rack delivered was just dumb luck. Don't think the tipping did anything to help, except he proactively let me know or I'd have probably missed out.
Root Down is a restaurant at Denver International (middle of concourse C, aka Southwest), and one of the best airport stops I've found. The wine bar Vino Volo is another strong option, and is at multiple airports including concourse C at DIA. Pairing a wine flight with a soup/sandwich combo is a real treat on a layover.