Man-Oh-Man.......THERE BACK!!!......or did they ever leave? I had those in '67 on my CB450........Yes, Mark, get a pair of straight and upswept if you want. I have seen them mounted to a GL1000 Cafe build. Just be sure you get the correct reducers.
This style of muffler has been available in England since the '40s and was stock on BSA Gold Stars in the late '50s and early '60s. They are usually referred to as a Bell-Cone or Trumpet-style.