I wonder whether some of the concerns about an increased number of drones and the additional work is justified:
  
1.  A well-respected researcher shared with a group of us his work on the # of drone cells in the brood nest and the effect on honey production.  I won't give his name as the data are still unpublished.  He has demonstrated that normal hives will always contain 14%-22% drone cells.  If the bees do not have this number they will make them by enlarging worker cells or through burr comb.  
    The researcher set up two-hive pallets.  In the spring he removed all drone cells from each hive.  In one hive he substituted drawn foundation with no drone brood.  In the other hive he provided drawn drone foundation so that drone cells amounted to 20% of total cells in the hive.  This experiment was run for three years.  15 pallets (30 hives) were used.  The results were the same in all three years, and the hives without drone cells averaged 100% more production than hives with drone cells!  (60 pounds compared to 120 pounds.)
     Was the increased yield from not having to feed drone larvae, or from having to fuel flying drones?  This calculation turned out to be simple, and the drop in yield in the hives with a normal drone load was due to having to provide fuel to flying drones.  There was only a minor drop in yield from having to raise drone brood.
  
2.  Varroa females do not enter cells until 1-3 days before they are sealed.  Therefore if drone foundation is used the beekeeper only has to be on a once in three-week schedule for removal and freezing of larvae.  Moreover, the extended period that drones are in sealed cells (which is why the mites prefer the drone cells) means that if a beekeeper is few days or even a week late that no damage is done as the cells will still be sealed.  
  
I removed and froze drone foundation this year.  I managed three cycles, but should have done four. (We only get 5-6 cycles here in the Northeast.)  Nonetheless, I killed "most" of the reproducing mites, while saving myself a lot of honey from not having to fuel flying drones.  This year, for the first time I can remember, in mid-August I still have plenty of drones in the hives...which I view as a healthy sign.  (I will pull honey and treat beginning next week.)
  
I did this with approximately 75 hives this year.  Two frames of drone brood a hive.  This surely is impractical for commercial beekeepers, or for sideliners with much more than 100 hives.  However, it is certainly practical for hobbyists.
  
As for selecting for mites that prefer worker cells.  Think about the math.  Using 20% as the "natural" number of drone cells, that means the equivilant of 4 frames of drone cells out of a two-deep brood nest.  If I supply just two frames of drone foundation, I am only supplying 50% of the number of drone cells likely to be used.  Lot's of room for more drone larvae, while still killing lots of Varroa mites.


Lloyd
Lloyd Spear, Owner of Ross Rounds, Inc.
Manufacturer of round comb honey equipment and Sundance pollen traps