Additional tabbed regions

The URL custom properties for displaying tabbed regions allows three different positions for displaying the tabbed regions in the right sidebar, but only one option (in center-one-index at the top of the page) in the main column (the 620px left column on our wireframe).
(http://docs.townnews.com/kbpublisher/How-can-I-display-tabbed-regions-on-my-site_6620.html)
We would find it useful to have the option of placing a tabbed region in other positions in the main column — for example center-one-index, center-four-index, center-seven-index or center-ten-index.