OK, my favorite "blue bitones"
Queen of Elegance - Barry Blyth. Can't say enough good things about it, easy grower, heavy and reliable bloomer, serene colors. I sometimes informally judge irises based on how long I can sit and look at them. I could stare at this iris all day long.
Blue Trill - Paul Black. For years I tried to find the "perfect" light blue iris and this one is really close. Smells great, too. I can never get a picture that does it justice, though.
T-Rex - Gerald Richardson. Like many of Gerald's iris, BIG flowers on equally husky plants
Ascent of Angels - Mike Bernard. This might be the only iris he introduced?
Raging Tide - Keith Keppel. Got to love those ruffles!
Jordan's Joy - Schreiner. I think this is one of the best iris Schreiner's has introduced in the past decade and am surprised it didn't get more recognition. Another one that I take many pictures of, but never quite capture.