I currently have a Sony NEX-VG10. I would like to know if it's possible or worthwhile to get a 3D lens for it? I did a google search and can't seem to find any — or am I blind?
It's certainly possible; your camera has E-mount; you could use adapter for A-mount lenses together with a 3Dstereo lens. Perhaps slightly more known is Loreo 3D lens, that comes in Sony/Minolta A, Canon EF, Nikon F or Pentax K mount and could be used with adapter for that mount. Or, you could combine an adapter for four-thirds and Panasonic 3D lens.
As for if it's worthwhile - only you can decide that. You can search for results others have achieved and think if it could be a worthy addition to your images/videos. Some find that a special camera (such as Fuji FinePix Real 3D W3) does the job better, mostly because the distance between lenses is closer to human vision, you have live preview of the result, control over zoom and aperture, and you have full resolution for both images.
For 3D photos of still scenes, an alternative is to attach your camera on a focusing rail on top of a tripod so that it can ride sideways, and using manual mode and manual focusing (for making sure nothing changes between frames) to take separate frames for left and right image, and post-process them into a 3D image.