This can be a very difficult and frustrating problem in my experience. I had/have the same issue with my Galaxy Tab 7.0 Plus tablet running Android 4.0.4. I have tried to track down the offending app with no success. Running in Safe Mode the battery drain by Google Play Services does not occur. However, deleting all downloaded apps, even doing a factory reset and with no downloaded apps installed the battery drain caused by Google Play Services is extreme. This battery drain issue started a few weeks back with no new apps installed at the time. It just started out of the blue one day but I suspect an update of Google Play Services installed automatically may have triggered it.
I have given up trying to resolve this issue. I have uninstalled Google Play Services and do not have any apps that require Google Play Services installed. So far that is just Youtube and any updates to the Maps app. My battery life is excellent running in this configuration. Every so often Google Play Services will mysteriously get reinstalled and I immediately uninstall it again.
This tablet and Android 4.04 are an old and largely unsupported platform now and I consequently doubt that Google will ever resolve this issue. This tablet is not my only or primary device now. I use the tablet mainly as an e-book reader, crossword and solitaire game, occasional Internet browser and a few other applications. Not the ideal solution but it works for what I use the tablet for.
Interestingly, I also have an old Kyocera Event phone running Android 4.0.4 with Google Play Services installed and have no battery drain issues. I have very few apps installed on it and use it pretty much exclusively as a golf scorecard and GPS.
I sympathize and share your frustration.