I used a home-made push-in cage made from #8 wire hardware cloth to introduce my Russian Queen last summer. It worked very well. Frame of capped + emerging brood, pushed in the wire cage, introduced the queen and her itinerary, pushed a little gate over the opening, and put the frame in the hive in the middle with another frame removed to make room for the cage. The bees chewed away the comb around the base of the outside of the cage, and they also built comb hanging from the inner cover to fill the gaps on either side of the cage. Other than that, the introduction went very well.
Making the cage was simple - I am at work now, but I will try to remember to take pics and post them later.
Grid.