I have been buying these from Whitechapel but of late the size selection has diminished and the quality suffered. The last I bought were drilled for #6 screws and counter sunk for #5 and the finish was not as good as in the past.
When I was at WIA there was a company there called Phoenix Lock. They had samples of their product on their table and it looked like very nice quality stuff. I know that they do carry extruded brass hinges - fast tip, button tip or ball finial. You can reach them at www.phoenixlock.com or 800-471-3087. They're also (or at least they were) offering a 15% discount if you mention "Woodworking In America".