Jim,
One Stop Fire Protection has brass and chrome. You'll have to contact them to see if they have a Halotron unit (a Halon replacement) in this design. If not try the others shown I'm sure someone can help you.
http://www.onestopfire.com/extinguishers.htm
http://www.afprotect.com/portable.html
http://www.halotron-inc.com/
Halotron 1 (HCFC Blend B)
Amerex Corporation
Craig Voelkert
7595 Gadsden Highway
P.O. Box 81
Trussville, AL 35173-0081
205-655-3271
205-655-5112(fax)
http://www.amerex-fire.com/sales/halotron.html
sales@amerex-fire.com
Badger Fire Protection
Eric Moore
4251 Seminole Trail
Charlottesville, VA 22911-8272
804-973-4361
804-973-1589(fax)
http://www.badgerfire.com/
Buckeye Fire Equipment Company
Bryan Bower
110 Kings Road
Kings Mountain, NC 28086
704-739-7415
704-739-7418(fax)
http://www.buckeyef.com/