I've got carbon fiber L & R airbox side vent covers and a 7" c/f look LED headlight shell on my R so my thought was to buy some c/f sheet and cut to fit on the tank exposed side areas and spot RTV glue it in place. If you look at the tank in the right light it almost has a c/f pattern to it now. You could also buy c/f looking self adhesive sheet - I've got some on my dirt bike front # plate and it actually looks pretty good - almost matches the actual c/f side # plates, or you could use colored or diamond plate s/a sheet - lots of possibilities.
Way, waaaaay back I sort of remember that there was a member who made some "one-off's" for a group buy for the R-- but that was maybe eight years or so ago? Never saw any made commercially for purchase-- the R was (and is) the redheaded step child of the redheaded step children.
Your best bet would probably be to template and fab your own.