So yesterday Microsoft and the Azurestack Team released the final TP3 before GA that will, based on the communicated info, be released in mid-2017

Here you can download the TP3 to try out 

info from MS blog:

What’s new in Azure Stack TP3

With Azure Stack TP3, we’ve worked with customers to improve the product through numerous bug fixes, updates, and deployment reliability & compatibility improvements from TP2. With Azure Stack TP3 customers can:

• Deploy with ADFS for disconnected scenarios
• Start using Azure Virtual Machine Scale Sets for scale out workloads
• Syndicate content from the Azure Marketplace to make available in Azure Stack
• Use Azure D-Series VM sizes
• Deploy and create templates with Temp Disks that are consistent with Azure
• Take comfort in the enhanced security of an isolated administrator portal
• Take advantage of improvements to IaaS and PaaS functionality
• Use enhanced infrastructure management functionality, such as improved alerting

Shortly after TP3, Azure Functions will be available to run on TP3, followed by Blockchain, Cloud Foundry, and Mesos templates. Continuous innovation will be delivered to Azure Stack up to general availability and beyond. TP3 is the final planned major Technical Preview before Azure Stack integrated systems will be available for order in mid-CY17.

good luck!