I've managed to get the existing WPF controls; DatePicker & Calendar themed as part of Material Design in XAML Toolkit as described in this blog post.
But the fun part was cranking a couple of brand new controls to build the Material Design time picker experience:
These are sibling controls to the existing DatePicker and Calendar controls. I wanted to keep the API experience similar so you can dive straight in without any kind of learning curve. The Clock can be used in isolation, or use the DatePicker for an easy picker/popup/drop down behaviour.
Here's a static glimpse at the picker:
And here's a gif of the clock in action:
There's nothing complicated about using these, but you will need to get Material Design In XAML Toolkit referenced and set up in your app. Follow the initial tutorial, and head over to GitHub to download the source/examples project.