I bought one off ebay recently from a UK supplier : £20 including postage.
"UK 43mm WIDE ANGLE LENS FOR PANASONIC NV-GS500 NV-GS400"
The general quality seems very good. I haven't used it much yet, but so far the image quality when using it seems OK on my HDC-HS20.
A bonus (which I haven't tried yet) is that the rear element of the lens can be used alone as a macro/close focus adaptor.