Well, Gill himself once made an Arabic (during a sojourn in Egypt) but: it wasn't meant to match Gill Sans; and it was somewhat freaky so was never published. A while back* there was an article about it (embarrassingly called "Gill Sands") in Print magazine (in which the dunces actually managed to put one of the illustrations upside-down).
* I just checked - it was exactly 14 years ago.
hhp




If he doesn't, I would love to hear one. Not fair, but you peaked my curiosity. Particularly considering my first thought after reading the initial post was "how the hell can you turn Gill Sans into an Arabic script and have its idiosyncrasies translated appropriately?".