Yep. A lot of groovy adoption is "under the radar" precisely because it blends so seamlessly with Java. It may just be a build script or used in unit tests, but it is popping up all over the place.
Also under the radar because such companies using Groovy sometimes ask us to not speak publicly about the fact they're using Groovy... to my great disappointment!
Names that can't be given and numbers that can't be proven are no names or numbers at all.