You'd have a hard time removing anything that isn't a texture, I guess. You can't tell Dolphin not to render certain models on-screen. Gecko and AR codes might help in this regard, but it's probably a lot of work to get what you're after.
Not ideal, but you could just take plain screenshots and use a good image editor to clean things up to isolate whatever you're after. Not perfect, but practical (on a small scale at least).
Not ideal, but you could just take plain screenshots and use a good image editor to clean things up to isolate whatever you're after. Not perfect, but practical (on a small scale at least).