Microsoft has released the December 2016 edition of their evaluation and licensed Windows developer virtual machines (VM) on Windows Dev Center. The VMs come in Hyper-V, Parallels, VirtualBox and VMWare flavors. The evaluation version will expire on 8 April 2017.
If you don’t currently have a Windows 10 Pro license, you can get one from the Microsoft Store. If you just want to try out Windows 10 and UWP, use the free evaluation version of the VMs. The evaluation copies will expire after a pre-determined amount of time.
The Azure portal also has virtual machines you can spin up with the Windows Developer tooling installed as well!
If you have feedback on the VMs, please provide it over at the Windows Developer Feedback UserVoice site.