We deployed about 200 Windows 7 desktops last summer with Fog and I’ll share what we did:
Build one machine as master
Run sysprep /oobe /generalize
Fog pulls an image from the master to the Fog server
We use Multicast to send images out to the other computers.
When the computers boot, they run the mini setup, ask for computer name, etc.
One thing is we use KMS licensing so individual computers do not have a license key. Depending on how you license, there may be additional stuff you need to do.
i am not saying this is the only way, but this worked well for us.