Tried searching for a thread and didn't really find anything relevant but I had an idea. Let's say a ship, in this case I'm going with the Galaxy X dreadnought from TNG, is refit with two different types of nacelles. For example, the ship has galaxy style nacelles on the right and left pylons like normal, but the middle pylon has an Akira or Sovereign nacelle. I came up with this idea when brainstorming concepts for a new ship in my headcanon TOS universe. I liked the design of the Baton Rouge class, but it has a near identical twin, the Nordenskjold class. The classes looking nearly identical bothered me until I toyed with adding an additional nacelle either on the top of the saucer or the top of the engineering hull, making this ship analogous to the Galaxy X to the Baton Rouge's Galaxy if that makes sense. However, the stubby Baton Rouge nacelles looked weird to me, so I added a longer TOS era nacelle instead. I don't know if it looks weird or even would work.