I did mine in gloss black and it looks great but doesnt stand out.
It is infact possible to paint the calipers while they are still on the vehicle. You just have to spend a long time preparing them and masking off various areas.
Use wire brushes, steel wool and brake cleaner in an aerosol can to clean the brakes properly before painting or the paint will flake off.
With respect to the NISSAN logo, i tried two ways to leave it silver. I tried masking it off and cutting very finely with a razor blade and then i tried just spraying the whole thing and cleaning off the NISSAN logo with thinners and a rag.
The thinners+rag method worked about a million times better and gave an outstanding result if you attack the NISSAN logo while the paint is still wet.
I used VHT Brake Caliper paint which i purchased at Autobarn.