Yes, this type of analysis is possible in Tableau and it relies on a database with native geospatial analytics. Some examples include Teradata, Netezza and SQL Server 2008. You can find some examples of how this is done in Tableau in this blog post: http://www.tableausoftware.com/blog/tableau-teradata-geospatial
Additionally a session from the 2009 Tableau Customer Conference covered advanced mapping techniques such as the one you describe. You can see a webcast of this session or download the slides from here: http://www.tableausoftware.com/videos/advanced-mapping-techniques
There another interesting approach discussed here:
And now with parameters, the field "Center_PLZ5" in the provided workbook can be a parameter instead. If you do open the workbook in version 6, do not upgrade the extract, because the calculations rely on pass through functions, and the new Data Engine does not support pass through functions.
Has anyone done a whale curve with Tableau
I am not entirely sure what you mean by "whale curve", but from what I could see from a Google search for the term, I am guessing you are asking for a Pareto chart, and if so, see http://www.tableausoftware.com/learn/tutorials/on-demand/advanced-charts-pareto for a tutorial on how to make them in Tableau.