More antiques inspiration can be found at the American Folk Art Museum website. Selected artwork from its collection is also available as reproductions, and can be ordered from the museum's Book and Gift Shop. Shown above is one of its most popular pieces, Girl in Red With Cat and Dog by Ammi Phillips, dating from the 19th century and available as a poster.
More interesting links:
Museum of International Folk Art
Mingei International Museum
Japan Folk Crafts Museum