Some resistors SMD are made with PGM, platinum group metals , thin film google it see what you come up with, let us know what you find in your search of this subject.
example:
http://www.google.com/search?q=SMD+resistor%27s+platinum+group+metals+thin+film&hl=en&gbv=2&gs_sm=12&gs_upl=1938l19298l0l22174l20l20l0l11l4l0l63l546l9l9l0&oq=SMD+resistor%27s+platinum+group+metals+thin+film&aq=f&aqi=&aql=