You can use the ember-deploy-s3 and ember-deploy-s3-index addons with Google Cloud Storage by using interop tokens and the specifying endpoint in the configuration.
Google has a mode that mimics S3.
Tokens about this token and how to generate it can be found https://cloud.google.com/storage/docs/migrating#migration-simple
Add endpoint: "storage.googleapis.com"
to each of the config blocks.