3D bar plot

[jbaltrus]

I was wondering if with all this beautiful new 3D development, bar plots can be plotted with 3 axes, such as the one below

[jeremysanders]

I have some code I intended to include, but I wasn't 100% satisfied with it. The main problem is that the current 3d code often gets the ordering wrong for plots like this (due to the simplistic painter's algorithm). I should have another look at it...