In a large mixing bowl, cream butter and cream cheese until smooth. Beat in vanilla. Combine flour and salt; gradually add to creamed mixture. Divide into 3 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 x 9 inch rectangle. Combine pecans and sugar; sprinkle over to to within 1/2 inch 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 inch slices. Place 2 inches apart on lightly greased baking sheets. Bake at 400 for 12-14 minutes or until lightly browned. Remove to wire racks to cool.