You can save(under share) to Google drive already. If you wanted to access files on Google Drive you can use an app like Foldersync. It syncs the folders from cloud storage to folders that you select/ or create locally. I use it to to sync my Dropbox, Google Drive, Skydrive and Box.net files to my tablet. Once the file is synced locally on the device, PS Touch can see it if its a format that it will support. It's a workaround but it works.
I doubt that PS Touch will ever be able to save files to another service directly since it's in competion with their own Adobe Cloud Service. It works fine for my workflow but I can see how it may deter others from using PS Touch.