VW use to put them out, plus we got one from KMart many years ago, for our Mazda E1600, and we loved it I wouldn't know where you would get one today, you may have to have it made.
Yes we have had them in previous years. I have not seen one for a while. My suggestion might be to contact Trakka who are still around and making conversions. If they do not sell one they might have a supplier who could supply, or even make one for you.
There was a canvas maker near us before that would make things and we had covers made for expensive equipment at work to protect it, but they retired a while back. There would be some around if you look hard.
Doesn't seem to be much about for the tailgate, but if you had a side awning there are options of attached privacy screens or a screened enclosure or a annex.
