First off, thanks for the suggestions and advice. Here's what I did this weekend that ELIMINATED the odors. I sanded the floors because my wife wasn't comfortable with all that urine and odor being trapped in the joints between the hardwood strips. Then I vacuumed and sprayed KILZ along the edge (between the hardwood strips and the wall - there's a gap there.) Finally I covered the floor with shellac; using a roller it went quickly. Others may have found it effective to just cover the floor with urethane, but I'll tell you that I breathed easily last night.