Graham Kleinschmidt has carried out research on queen banking.  He has a paper
titled "Banking of Queen Honey Bees" and is 14 pages long.
 
He looked at free flying hives both queenless and queenright; non flying
packages with 1.5kgs bees and mailing cages.
 
His final sentence is "This research indicates that queen bee storage in
nucleii is preferable but as such storage is not always practical, queen
banking might be used for the equivalent of one queen production cycle
(20-25days) with the minimum of detrimental affect if queen bees are properly
stored.  Flying colonies of quiet temperament, preferably queenless and
broodless or queenless and broodright and fed pollen and sugar ad lib provided
the best results."
 
If anyone wants a copy by snail mail let me know and I will photocopy it.
 
Trevor Weatherhead
AUSTRALIA