I believe the Marving system will fit the RB and is a reasonable replica at a fair price however some club members have reported problems when trying to make it fit under RC/RD fairing. See in the for sale section of this forum as DanielB had one for sale for that reason.
Dave king only made silencers they are a very good replica that most would find difficult to tell from the original Honda system. Unfortunately after a lot of work by both Dave and club member RoyK there was little interest in these silencers (I believe 5 sets were made and sold) so Dave will only make them when he has time. I know the last sets made were on order for 2 years before they finally got produced.
There is also the OS stainless system which again is a reasonable copy and will last longer than the original system, clearly there is a cost for any stainless system and it will need coating but should last the life of the bike.