This video shows the work the team from the University of Pennsylvania GRASP Labs has been able to accomplish. These Quadrotors are able to lift heavy objects into various precise positions to build something. The team created a special gripper to lift the parts, the parts have magnets in them to assist them to snap together. Around the 1 minute mark in the video you can see many quadrotors working in unison. When you watch the sped up version it reminds me of a bunch of insects working together. One thing I would like to see is a coordinated multi-quadrotor lift.
Thanks for the tip John.