Hi Doug!
Good question you posed!  Some of the mail on the b-l, indicate varroa is to
blame.  Well, this has not been absolutely proven to be the 'whole' truth.
Yes, sure, there is a certain link between varroa and deformed wings.
  But at least some current research is generally heading in the direction of
varroa the vector!  A carrier of viruses etc.
So, there are a number of useful things you could be doing.
 
1.  Send a sample of bees away (30-50 bees) for viral analysis. Put them in a
match box. (I have no idea where you would send them in the U.S.A)
 
2.  For colonies with serious wing damage, try and record the mite drop per
day.
 
3.  Certainly treat your colony with an acaricide if you have varroa!
 
And you could consider looking at the following references
 
DeJong,D. et al (1982) Weight loss and other damage to developing worker
      honeybees from infestation with Varroa.  J.Apic.Res. 21(3):165-167
 
Marcangeli,J. et al (1992)  Malformations produced by Varroa on Apis in the
      province of Buenos Aires,Argentina.  Apidologie 23:399-402.
 
Bailey,L.& Ball,B.V. (1991)  Honeybee pathology (2nd ed). Academic
      press,London.
 
Anyway, good luck and let me know how you got on!
 
Cheers Peter