Leaflet is a great lightweight JavaScript module for showing all kinds of maps – but not really small ones.
The next version 0.8 (currently dev) helps with that.
The next snippet creates a CRS called Metric, while similar to the Simple CRS, this one has a scale of exactly 1 meter and is not bounded by degrees of latitude/longitude.
Additionally, the next snippet is a patch to the Scale Control, that goes away with the Earth CRC and uses our custom one to display a perfect meter scale (and imperial, bah).
Update 15.7.2015:
https://github.com/Leaflet/Leaflet/commit/daac1ca559670b16c7f19e8758978d1b335ad57f
An example custom map is here.