I recently modified the Axes method boxplot so that the confidence intervals around the mean are computed not with a static formula, but by bootstrapping the median as many times as the user specifies. Also, I commented out the lines that prevent the boxplots from folding around the hinges (but that's obviously minor and in the current SVN if I'm not mistaken).
Is this something that would be worth including in matplotlib? I've never contributed to a project like this before and my code is probably pretty sloppy by MPL standards. I'm not really sure what's appropriate to contribute and what's not.