Short term, you can always stream via dishanywhere.com right? It IS a windows box.
I have a windows Tablet (HP Stream 7) but I haven't tried dish with it yet. (I use it mostly at work)
On Windows 8, yeah, the website kinda works. Haven't tried streaming with it.
On Windows Phone 8.1, the website is a complete train wreck. I don't even need streaming video on my phone, just a good guide and a way to set recordings.
With the new developer tools and Microsoft combining the Windows Store with the Windows Phone store, one can write a universal app that will work on both. Only the UI views need be different between them. If not for Windows 8 and Windows Phone 8.1, then I hope they'll get something out for Windows 10.