Google and eBay are your friends.
There would be thousands you can use both aftermarket and re-purposed from other vehicles/places. Old Fridges and appliances used to have these type of finishes including jukeboxes.
And there is always the factory OEM Triumph accessory list for Touring panniers and rear guards blades that could be adapted to pannier use. These are solid steel chromed and I have six (6) I was going to use them to make a Solo seated fender rack using 3 or more attached to the rear Rocket guard. The curve matches the R3/Roadster as well as the Touring models' rear guards, but once I got Red Striped body-tins and a RIVCO rear solo rack I changed tack.