Hi Jackie and David - I did see the challenge you linked to here Jackie, but all of the examples seemed to go more of a branched scenario direction... I'm not sure I saw any that kept any sort of semblance of a decision tree (graphically, anyways), but I may have missed some.
I'm getting ready to tackle a project where I'm going to provide a downloadable/printable decision tree graphic, but am toying with the idea of using Storyline to also produce an interactive decision tree that would be accessible on both laptop and mobile device.
I thought it might make for a cool elearning challenge, if it hasn't been done already. Jackie, I'll go back and browse the submissions a little more thoroughly, and thank you!