S1 IS Telephoto Lens

Hello all,
I just bought an S1 IS and I'm very happy with it. As much as I like the 10x zoom, I'm looking for a Telephoto Lens adapter. I know Canon makes a 1.6x for this camera but I was hoping to find at least a 2x. Anybody have any experience with 3rd party telephoto lenses for this camera? Does Canon make a 2x for this camera?
Your input would be apprieciated.
Thank you.
Jay

I thought I had read that Canon made a 3x telephoto adapter for this camera but maybe it was actually just 1.6x. I also would like to know for sure if a 3x is available for the S1 IS. I do have a 3x for the A70 which seems to work quite well - but for obvious reasons I use the S1 instead for all those distance photos - I can zoom in more closely; there are fewer lens surfaces to compromise the picture quality; there is much less trouble to set up for taking such photos.