Didn't realize we had a availability thread on this. My wife and I used ttptracker.com to get an appointment before our mini vacation. It's a site that helps you with finding global entry interviews/appointments. I believe it also works for other travel programs like nexus. There's a free option that makes noises when an appointment is found but you have to sit around the computer. We used the SMS one and it's cheaper than the other ones in the market like appointmentscanner. Thought I'd share this with others struggling to find appointments it's a pretty valuable tool.