Ever since I found out that the planets would fit neatly into the gap between the Earth and the Moon I've been toying with it as a tattoo idea
Uranus is 4.5 billion km from Sun and if, for the sake of simplicity, the model is 4.5m wide, that would mean that Earth with its diameter of ~13000km would be a speck just 0.013mm wide. That should be 1/10th of a single dot at a resolution of 200dpi if you are planning to print a map (one dot at 2000dpi but good luck printing that;). You might want to consider adding an arrow and a label.
But in a right scale. If the earth has a scale of 1/10th of a dot, that would be a bad decoration
Allegedly the first. Sorry, didn't find any english link, but clicking on the 'Virtuelle Tour' there leads you to at least some maps where you can see how it is spread out through the city.
But I can't have that in my bedroom