I have same issue when i moved to richfaces 4.
Can you please provide some pointers of sample code with rewrite pieces to replace ExtendedTableDataModel ?
Sorry, I can't, because we did not move to version 4.
If you visit the 4.0 Demo page, you can find ExtendedDataTable. According to the page, the table now uses the standard model.
If you click on the Selection Management tab, you can view ExtSelectionBean source, which shows how you can manage table selections.