The largest amount of laptops I've ever seen carried through security was 12. Each one was wrapped in bubble wrap and they were stacked in two neat rows of 6 in a good-sized rollaboard. By the time the bag followed the laptops through (each in it's own bin of course) it was empty. His biggest concern was possible theft, naturally, so a couple of us kept an eye on the first ones to come through until he was through and they were all together again.