We don't publish images quite as immediately as the other clouds since we run various test suites (it's supported by Google as well as Debian), but that's in progress too and we'll update the GCE images in the near future. The images are still built the same way as anyone else would, i.e. build-debian-cloud.
We're still on the shell version and without cloud-init, but thanks to Tomasz, we're starting to make a bit of progress on changing to the python version. :)
The new images do have some bug fixes, ranging from the ~10 commits we sent to build-debian-cloud to improvements to the Google integration code to a virtio-scsi memory leak fix which the Debian kernel team kindly backported to the Debian 7.4 kernel.
- Jimmy