I've got some shell scripts that can send network notifications to Growl for Windows, and it's working fairly well. Can Notification Center on 10.8 (or iOS devices for that matter!) be configured to receive these? Does it even use Growl's layer 7 protocol at all?
Mountain Growl will route Growl notification through Notification Center. This way your scripts could still send the network notifications to Growl and they will show up in Notification Center.