We are requeening our hives using Steve R's no-kill method. On the right, the Big Purple hive and the new purple nucleus hive. The nuc. hive contains the new Russian queen from Olympic Apiaries, along with ready-to-hatch brood and a lot of young workers from the Purple hive, and honey. Later in the summer we'll combine the two hives, with the nuc. hive and young queen on top.
This method allows you to requeen without killing the old queen, or even finding her. Putting the new queen on top and making sure she has lots of workers and a strong colony on her side seems to be the trick.