I've heard of foundation that has cells intermediate in size between
drone and worker cells.  The idea is it can be used for honey without
use of a queen excluder, since the queen will not lay eggs in cells of
the weird size.  Does this work?
 
>      Note:  I keep my hives fairly clean of burr comb and the drone
> population is fairly insignificant except in one hive where the
> queen crossed honey and laid in the test drone sheets (I had
> "thousands" of drones before I figured out what she had done).
...
> Further observation (although probably unrelated):  The colony
> where the queen crossed the honey to lay has a verroa mite
> infestation.
 
Probably _not_ unrelated.  Varroa prefer drone brood to breed.  You had a
varroa breeding chamber for a while.
 
Apparently a chemical-free method for varroa control is to add some drone
foundation to the brood chamber.  After the cells are capped but before the
drones hatch the frame is removed and the brood destroyed.  More drone
foundation is added.
 
Don't do this if you aren't sure you can get back in there before the brood
emerges.  Else you may be breeding varroa!
 
-Mike