A Haunted House for Halloween. This stands about 60mm high at its default size. The yellow-lit houses in the picture are printed at that size, with the orange-lit one printed at 133% in X and Y. I left Z at 100% (that's the depth of the house – it's printed on its back).
Slice this and upload the gcode to http://gcode.ws (for example), then look for the first layer that consists only of windows, right near the end of the print. Insert your filament-change gcode immediately before that layer and you're all set. I've uploaded what that layer looks like for me when I use code.ws.
Alternatively, print it in one colour and then dab paint onto the door and windows – or perhaps use glittery nail varnish? Just a thought :-)
Two perimeters is enough, at least two bottom layers and at least three top layers.