Here's a different solution to illuminating your bathroom for successful visits to toilet during the night: the phosphorescent bathroom. No nightlight or dimmer would be necessary to help guide your drowsy and stumbling self into the right spot, for these products emit their own glow.
Deb Wallace entered this design into the 2013 Reece Bathroom Innovation Awards, and it's pretty compelling. The proposal suggests the use of phosphorescence in the materials that make the rim of the bathtub, the edge of the sink basin, the toilet seat and the faucets and flushers. During the daytime hours, the pieces would soak up the sun's rays through the washroom window and the phosphorescent bathroom set would begin to radiate neon green in the evening and last for up to eight hours.