An American source for brass tube, rod and sheet is here:
Lewis Brass and Copper Company, Inc.
Catalog:
http://www.lewisbrass.com/newCatalog/NewCat.pdf
Phone:
1-800 221-5579 (U.S. only)
Phone:
(718) 894-1442 (Outside U.S.)
Fax:
(718) 326-4032
Email: