[development] Table hook idea

[Mike Cantelon]

Sean Robertson wrote:
> Got any examples of specific use cases?
For example, if you'd like to add a column to the admin/content/node 
hitlist table that would show the thumbnail of any image, you'd be able 
to do this by adding a column using a row_alter hook. You can currently 
do this by overriding theme_node_admin_nodes, but you end up having to 
duplicate 30 or so lines of code.

Mike