Just wanted to post this to share my experience with everyone else. The Gen 3 Prius is specified with 26" for the driver's side (left hand drive) and 19" on the passenger side. I've wanted a slightly longer wiper on the driver's side for better coverage so when I replaced the factory wipers I decided to go for Bosch Icon blades at 28" (two inches longer) and 17" (two inches shorter). There is no interference of the blades and the coverage is modestly improved. Additionally, the passenger blade no longer looks like it is hanging off the edge of the windshield. I'm happy with the results. Based on the overlap of the wiper pattern, you might even be able to get away with a 15" or 16" passenger blade and still have full coverage.
