Steps as follows:
- Create a new Windows 10 KVM guest with the regular Intel NIC (default) with one IP.
- Install as usual.
- From the guest's Cloudmin page, navigate to System Configuration -> Network Interfaces
- Select the first IP, and change the Network Device Model to anything else - I used VirtIO.
- Reboot the guest
What happened: The guest still has the default Intel NIC as shown from the network interfaces list inside the guest OS.
What should have happened: The guest should now have the selected device model.