My favorite harnesses are ipuppyone. They are similar to Puppia but less expensive (I am a bargain hunter!!) but I especially appreciate them since they are durable and I can toss them in the wash without them getting worn out. There's quite a few suppliers online, but my absolute favorite website to order them from is
http://www.pupincloset.com/
They have quite the selection, and lots of mesh ones too. =) Hope that helps!