AFAIK, no. I was searching for a lightgun solution a few months ago, and Saturn's was one of the guns I looked up.
If you visit here much, you will have seen the lightgun threads. Act labs, or guncon2 are your good choices. See
my website for more information on the guncon2 solution.
Btw, as zsnes doesn't support absolute mice yet, the best snes option is snes9x.