Many beekeepers in Australia are using a two queen system of beekeeping but it
is a horizontal division and not a vertical division as used in the USA.
 
It is normally 10 or 12 frame boxes divided horizontally into 2X5 or 2X6.
 
They are not easy systems to work but some can work them very successfully.
They will produce a lot of bees which is a big advantage for targetting a
particular crop.  The biggest problem is the bees will kill one of the queens
if the conditions "go off".
 
There are many tricks to working the horizontal system such as facing the
entrances of the boxes such that one is facing north and the other south.
This minimises drifting.
 
They do work but it takes some skill in keeping them going.
 
 
Trevor Weatherhead
AUSTRALIA