Love those African Sunset petunias, Caroline.
I also am crazy over yellow/purple (blue) combinations. I think it may have been Park seeds that had a blue/yellow petunia combination that I loved.
I'm always disappointed when some of the bicolored plants (such as petunias) end up reverting to all of one color. The best luck I've had is with some of the Proven Winner plants. I absolutely loved their Pretty Much Picasso--held up well as a bicolor all season long. Unfortunately, must buy plants.......no seeds