I'm in the process (first stages of the mock up) of designing and fabricating my own sissy bar/bag rack..the cost of and the "no imagination/bolt together" rigs offered by everyone just doesn't do anything stylewise for the Rocket..mine will be a low profile 6" tall one piece design powder coated or brush stainless with a small platform that will follow the curve of the fender (no real reason that says a bag rack has to be flat) and end at the tail light..the backrest pad will be a small horizontal oval (similar to the harley style) to follow the theme of my aftermarket oval mirriors..... when I get this design off the paper and in the first model I will try to get a photo to those who would be interested..I have no interest in marketing this idea but can share the design and how to make it...
I've got a Corbin Dual Tour heated seat on mine and I opted for their backrest initially (I put the trunk on it for a little - VERY LITTLE - extra storage) but the backrest is too low for anyone's comfort or for attaching extra luggage. I just bought the Triumph luggage rack, tall sissy bar, and backrest - for me it looks like the way to go.
Alselec, Yes you can get the backrest by itself...not sure how it would mount on the Triumph seat. The Corbin has a square shaft and a threaded bolt that goes through a hole in the seat and into a threaded hole at the base of the shaft.