Several years ago I saw quite a few online stores in the USA selling them. I think those ones were held on just with double-sided foam tape. It's unlikely those were all sold. So someone would still have them. They were the more modern, narrower type though - tinted dark greyish-coloured - and only several cm wide, as opposed to the OEM type that was modeled on the cone of silence from Get Smart.
Not certain which type is less 'damaging' to the car though...
i.e. Be you sure you want 'em. Because I've removed a few over the years, and the stainless clips that slide under the door rubbers can leave permanent damage. And unless it's a heavily-garaged car that doesn't see the weather, they deteriorate in a few years, get crows-feet cracks, go cloudy, the strip of doubled-sided foam/tape at the top breaks down and leaks large drips anyway. Any one of which, means you'll remove them again and be left with ugly rubbers. (I still remember only noticing the stainless hardware vibrating off the last couple of threads at 120km/h, lol.)
For example, the lowest two clips slide under the rubber that prevents rain flowing down the glass and inside the door. The rubber conforms to shape over them, and hardens. And the ones at the top do a similar thing to the bailey channel. Causing the rubbers to turn from this _______ to the kind of shape below. Maybe not a worry to some, but I thought it was ugly, and I don't like water getting into places where it can sit and maybe start rust.