In a large bowl, cream butter and cream cheese until light and fluffy. Beat in vanilla. Combine flour and salt; gradually add to creamed mixture and mix well. Divide into three portions. Wrap each in plastic wrap; refrigerate for 2 hours or until easy to handle.
On a lightly floured surface, roll each portion into a 16-in. x 9-in. rectangle. Combine pecans and sugar; sprinkle over dough to within 1/2 in. of edges. Roll up each rectangle tightly jelly-roll style, starting with a long side. Wrap in plastic wrap; refrigerate for 2 hours.
Unwrap and cut into 3/8-in. slices. Place 2-in. apart on lightly greased baking sheets. Bake at 400° for 12-14 minutes or until lightly browned. Remove to wire racks to cool. Yield: 7 dozen.