After a quick hack, it's done - the Threadless size chart in centimeters may be found here, for the joy of Europeans and all other normal people in the world: http://mythreadless.info/size_chart_metric.

Original post was:

Inches, feet, yards, aaaaargh! Why can't you use the metric system? Seriously, Threadless should also have a metric size chart for non-imperial people like me.