I have already developed a gis template with many functions with the google maps extender. Now it's too complicated to switch on the other apis only for the baselayers 🙂
How about moving to the full ArcGIS API for JavaScript and using this sample to get Google Maps in your JS app: http://gmaps-utility-gis.googlecode.com/svn/tags/gmapslayer/1.0/docs/examples.html