Wow this is one brought back from the dead, but a great topic. Large transport Part 25 aircraft are not certified for spins because they have stall avoidance hardware in the flight control systems and no testing is required. Some of the smaller 25's have been spun, quite a few business jets and light turboprops. I can't say which was the largest, but I suspect Beech 1900s and some of the older airline turboprops without stall recovery hardware were spun during certification. Recovery is done with pyrotechnic drag chutes.