Yes, I figured he meant 5-gal, not 5-lb.  Or else he packed it with an
awful lot of pressure(!)  : )
 
You mentioned the spackling/dry wall compound buckets.  I would wonder if
the material is food-approved, or if the compounds might contaminate the
honey, even if the buckets were scoured clean.  I wonder if you could even
get them clean.
 
Any BEE-Liners have information to offer on this?  Could this be a good
source for bulk containers?  Many years ago I got 5-gal pickle buckets from
a caterer.  I used them, and certainly they were safe, but could never get
the dill-pickle smell out!