Is there a Tree Picker I can use?

Is there a Tree Picker I can use (or customize a similar dialog)?

There is no such component out of the box. Depending on what you need you may try to adapt Tree or Lookup with style provider.

Is this functionality available now or still missing? Is there an example to use Tree for this purpose?

Can you please elaborate on what do you mean by “tree picker”? Do you need a standard dialog, or component, or what else?

I want dropdown picker component with tree items. In case dropdown doesn’t support this, how can I use Tree component for this purpose? One more thing, my requirement is to allow selection of leaf nodes only.