I think its a virtual impossibility to get one with good relative distances. If you have a play with the model generator in the link below, you quickly see that unless you have Mercury as a speck of dust right next to the sun your model stretches to metres wide very quickly. You can ignore the planet sizes but relative distances is a bummer to do right. You might have to go digital to get what you want.
http://www.exploratorium.edu/ronh/solar_system/