Damien Alomar has been a fantastic resource to the Rhino / Grasshopper community.  You can find his work on his blog: http://liquidtectonics.blogspot.com/. Recently, Damien released a grasshopper definition that via a script component, reads whichever excel table is open.  This was the base for the following images and basic definition.

Another script component was written in order to filter the values (0-9) from the excel cells to different lists.  This way depending on the value of the cell one could place different geometries, etc.  Basic definition shows the distribution of the cells on the xy plane.  Some tweaks allow for a more flexible system where a user can populate a surface with this information.  Think of it as ‘paint by number’ for GH.

lan_excelfield.zip file with a sample excel document and basic definition.