This topic came up in today's Intro to Photoshop workshop. If you have a Mac and an iPad, iPad Pro with Pencil or even an iPhone, there is an app called Astropad that allows you to turn your iDevice into a drawing and creative platform. I have used it with the original iPad 3 and it worked just fine. Will be trying it with the iPad Pro and Pencil this weekend. It does require a Mac client be installed and I do not see an option to work with Windows.