This topic reeks. There was a confirmation already 7 days ago:

Defaced > Marley Gray [marleyg@MSFT]  • 7 days ago 
How does one get into the BaaS program? Expanse is on the template list but for some reason hasnt been "added"
 

Marley Gray [marleyg@MSFT] > Defaced  • 7 days ago 
I'll include it in the next update. Make sure you put keywords like blockchain in your ARM template.


https://azure.microsoft.com/en-us/blog/azure-blockchain-as-a-service-update/