The University College of the Cariboo,
BC, has recently constructed an Astronomy Walk which may be the world's largest
scale model of
the solar system. The driving force behind this project is Roger
Collins. Information for the Walk was contributed by a number of
Canadian astronomers. The project was submitted
to the Guinness Book of Records, but it was politely rejected,
apparently because "it could not establish criteria for `exceeding'
the project".
You can find out more at: http://www.cariboo.bc.ca/astro/