Seems like the 319/20 can carry a heavy cargo load. Was on a flight ORD-SJC in mid 2000s and pilot told us we had heavy cargo and would use the full length of 32L (starting at far end before the 9/27 intersect; same as Hong Kong bound 747). he didn't say what cargo we had, but it was one of the most unnerving take offs I've ever had as we did use most of the runway finally rotating by the hangars at the end of the runway with a low nose up position and plane just seemed to take forever to gain any altitude. Don't recall which Airbus, but thinking it might have been a 319. It was a full flight, so no one was moved around.