Hi, from what I know, only G lenses can be used on G bodies, you cannot put G lenses on other bodies (there is a company in Japan that converts G lenses to M mounts but at a very high cost on the order of US$600 or so) and you cannot mount other lenses on the G body. This is what I know
Having said that, G mount lenses are relatively cheap and I have seen a couple at The Camera Workshop in Peninsula and on ebay.
Hope that helps