i'm half asian, and i don't find the term offensive. neither do my asian friends. and we use the term.
what's lame though, is sometimes the term is used too liberally now-a-days. such as, some will comment on a nicely fixed up import (well, imho) or even just a japanese car, and call it rice.
the term "sour kraut" has been used in the past to describe german cars in the same context as "rice". are german people going to get offended by it? or german car owners?