Thanks Gdog42. I brought my monstrous board into AnyMountain last night for tuning (because I'm too lazy to do it myself). While there I found a pair of size 15 Burton Moto boots which I tried out in my adjusted NX2-GT XL binding. Being newer and having that footprint reduction just wasn't enough. However, it did come closer to fitting than my 2005 DC Judges. I'm just not sure what the deal is. Either I'm doing something wrong, my pair shipped with the wrong sized toe straps, or as I strongly suspect Flow is guilty of gross false advertising. I've emailed Flow with what I found but they've been unresponsive.
Wiredsport, I used one of those shoe store type foot measuring plates and it shows me at just over size 14.