Heres how I do mine. I buy aluminum round edge flat bar, rip it down the middle and use each half as trim. 1/4" wide I drill and use tiny sheetmetal screws, 3/8" wide I drill and tap and use machine screws. After I make it up I polish, but you could finish it however you want.
Clayton Machine Works sells premade trim in I think 3 and 6ft pieces. Just drill your mounting holes. But compared to making it yourself it can get pricey.
Heres 1/4" trim polished and installed