http://tapestry.markmail.org/message/efgdi7245vnzbmhb

gistfile1.txt

<!-- page.tml -->
<t:grid source="myCustomGridDataSource" ... />

// Page.java
public GridDataSource getMyCustomGridDataSource() {
    final List<Document> docs = documentDAO.getAll();
    GridDataSource wrapper = new CollectionGridDataSource(docs) {
       public int getAvailableRows() {
          return super.getAvailableRows() + 1;
       }
       
       public Object getRowValue(int index) {
          if (index < docs.size()) {
             return super.getRowValue(index);
          }
          return new Document();
       }
    };
    return wrapper;
}