MSDN Subscriptions just released windows 8 files on msdn subscriptions, you can get it with your subscription.

Windows 8 - https://msdn.microsoft.com/en-us/subscriptions/securedownloads/default.aspx?pv=36:481

Windows Server 2012 - https://msdn.microsoft.com/en-us/subscriptions/securedownloads/default.aspx?pv=36:483

Thanks
RV