This would be similar to plot lines except it would be a line against which each column would be compared to, similar to this image: http://i.stack.imgur.com/NOWBk.gif

It has been suggested by Highcharts staff on StackOverflow community to use a scatter series with a custom shape for the line, which would work fine. But I wonder if this is a standard enough feature on a column chart to be worth supporting in a more "native" way.