I know Airtran's res # will create non-rev PNR's but won't tell you exact loads. I used to call and create a non-rev listing when I worked as an intern in ATL for a charter company, then show up at the airport and show my paper ticket and pay the fees at the ticket counter. When I called the res #, they would say something like more than 6 seats available or it doesn't look good to non-rev. It would probably work for jumpseating although I have never tried. I just show up at the ticket counter.