> could we instead get an VM/container based solution that is deployed on-prem
I don't know the answers. My guess is this is very improbable. It goes against the entire philosophy of Meraki. Meraki used to support using an HTTP proxy, which might have helped in this case - but that support has also been dropped (proxies are typically an on-premise solution).
I tihnk what Cisco would tell you here is if you want an on-premise solution you can deploy into a VM farm - use Catalyst Centre.
IMHO, you use case it not a good fit for Meraki. It's a better fit for Catalyst Centre.