banding normal maps.

I am curious what the official work around is to the banding in normal maps. This banding is especially visible on very reflective surfaces.
while abrupt and simple angles like paneling grooves or nicks look fine, the smoother more gradual areas suffer some harsh banding. my "normal" solutions would be to dither or use 16bit png(even though pngs are the devil) as the normal map but it seems that unity or the standard shader at least doesn't play nice with 16bit.
![alt text][1]



just to show specifically whats going on here is an example of the problem. The area of the normal map that corresponds to the circled area has a very gradual slope. This is where some of the banding occurs.

i do hope there is just some import setting or something that i have been missing.
thank you in advance for any info or help.
-j