Cool, David.
Here's a link to a site that does the calculations for making a scale model of the solar system.
For example, if you make your model Sun the size of a baseball, Pluto (if it still counts) would be 4/1000 inches diameter, and nearly 1000 feet away.
Lots of other info and links too.
http://www.exploratorium.edu/ronh/so...tem/index.html
Enjoy,
Chris.