Perhaps you want to use a Cascade Chart? I wrote a tutorial in Variable Width Column Charts (Cascade Charts).

I am trying to create a chart that is essentially a stacked bar chart along the x-axis, while at the same time a clustered collumn chart with respect to the Y-axis.

The aim is to create a visual representation of possible improvement projects, mapping their contribution to a total figure (tons of CO2) horizontally, and also showing the individual net cost (positive or negative) in dollars.

Could you please tell me if this possible? and if so, how?

thank you for this posting, it was both useful and interesting. I have a question regarding the section that begins with “To add labels to the blocks in the chart”, I constructed the data in columns as shown, pasted them as new series, then deleted the rows of “0%”. however The markers at the 0% locations remain, so when i add the data labels they appear both at the center of each box and also at the lower left and lower right corners of the box at 0%. I am using Excel 2007. Any suggestions?

I had not thought of using droplines to create the vertical lines. Nice suggestion.

Now there is a choice between needing more rows of data (to force the area chart outlines to reach to zero) or more elements in the chart (the drop lines).

http://www.ultimatepres.com/create-marimekko-chart/info_13.html
“so they don’t have vertical lines between adjacent segments:”…

to get the vertical separators:
Format Data Series>Options> Drop Lines (with tick) (you can then format the drop lines to your satisfaction)