In article <330f50b3.36048692@news.pacbell.net>, billchau@pacbell.net says...

>Exists?

Yes, in two forms...
For non-bellows cameras (fixed camera body depth), there are
multi-element wide-angle converters made (mostly for video
camcorders and older, inexpensive still cameras), but image
quality for still photography is not generally very high...
For view camera lenses, simple weak close-up lenses (a +1
works well) can be added to shorten the FL, thereby widening
the angle covered (in the frame - total lens sharp coverage
may be reduced...). Image quality at the smaller stops usually
used with these cameras/lenses can be fine.
Hope This Helps