In Dallas, Texas, ANTIQUES ROADSHOW host Mark L. Walberg and appraiser Noel Barrett jump at an offer with no strings attached - a trip to see a private collection of more than 1,000 marionettes. At the Dallas Convention Center, appraisers uncover a virtual archeological dig in a desk: an heirloom 18th-century miniature whose drawers are stuffed with 300 years of family documents and history, valued at $100,000.