Last weekend's project: a queen castle
It will hold three 3-frame mini nucs. I built it with a 3/4" space on the bottom to accommodate swarm cells that might be hanging off of the bottom of the frames. The 'inner covers' lie directly on the tops of the frames. On one end, there is the opening to the middle nuc, the other end has openings for the side nucs at the corners. All openings can be rotated closed so that the box can be transported with bees in it. The bottom is solid and permanently attached - so I can also pull the dividers and use it as a swarm collection box. With the dividers pulled, it is a standard 10 frame deep hive body.
I haven't decided whether or not to drill vent holes for the nucs. Opinions?