This can be done by creating a very specific calculated field, similar to the following:
if State='Illinois' and year([Order Date])=2010 and [Order Priority]='Low' then 1 else 0 end
Then, change the Mark Type to bar or Gantt. Place the above calculation on both the color and the size shelf. Right click on the calculation on the color shelf and select Discrete. Then, edit the colors as desired. Also, edit the size legend so that all the sizes are set to largest.
Hope this helps!