has a plain black vinyl cover - no logo, no text. It came with the trailer (covering an old
tire), but I would have picked black over white anyway; the trailer is not white (it's kind of beige), and white wouldn't look good for very long with the dirt that accumulates on the back of the trailer.
If it had any advertising on it, I would probably go to the effort to cover or remove that, as I have removed (or refused at purchase time) the dealer badge or sticker on each of our cars. My vehicles are not billboards for retailers.
I think a moulded fiberglass cover in body colour would be nice. No, I'm not going to build one any time soon...