I’ll attempt to answer your question, It is my understanding that accessories for the Rocket from Triumph are pretty hard to come by. You may have to go after market with Corbin or another company.
If I’m wrong perhaps another member can chime in
Also since this is the introduction thread you may want to ask your question in a new post in the bear claw corner
Welcome from Minden Nevada. Dave Platt makes a few different shorties. I can put you in contact with the guy who sold me my straight pipe. I believe there are shorter versions of what I have.