This is in a way similar to what Omniture does with the ClickMap plugin.<p><a href="http://blogs.commerce360.com/archives/omniture_sitecatalyst/omniture_tip_sitecatalyst_clickmap_becom.html" rel="nofollow">http://blogs.commerce360.com/archives/omniture_sitecatalyst/...</a>
I know CrazyEgg has a nice overlay but its more color and heatmap oriented. I think thats a small feature to add in In-Page Analytics... Color coding the page would give more insights.