wild tomato seeds are available in the U.S. too:

a couple of sources (from web search)

http://www.southernexposure.com/productlist/prods/49803.html

http://www.naturehills.com/new/product/seeds_product_page.aspx?proid=1996&Campaign_id=69&user=shareasale&SSAID=120055

I'm sure there are others.  www.seedsavers.org also has several
interesting looking "currant"
tomatoes and one "mexican" tomato that are probably the wild tomatoes,
but are not identified
by species..

    Lynnet