While I know Azure Stack is very new I wanted to get this feature request out there right away so by the time we are implementing Azure Stack we will (hopefully) already have this capability in Orion. Azure and Azure Stack are critical components for us and our forward roadmap so any monitoring solution we use will need to fully support these going forward.
Below is a Microsoft article that discusses the integration possibilities with 3rd party monitoring applications including a Nagios plug-in. And seriously, if Nagios can do this then I know SolarWinds can both do it and do it better! 
https://azure.microsoft.com/en-us/blog/proactively-monitoring-cloud-operations-with-microsoft-azure-stack/