Khalil Maamoon is a good example of solid brass based narghiles. Also, the Syrians I post pictures of are a couple of others. Smiley's http://nargileclub.com/
carries a couple of such products as well. Heavy brass cores are a good idea because they never rust, never wear out, never pick up odor and are an indication of careful attention to build quality. Basically, as far as i'm concerned any rig worth buying is one that you should be able to leave to your grand children.