i suppose i would resort to emailing a short query to 10 or 20 manufacturers.

"shortest projection wall lavatory faucet"

Kohler has a K-2443 (discontinued, but available) which you install wherever you wish, inside a shelf that you build to suit your space. In a tiny space, a shelf is your friend. The k-2443 has a single-handle temperature mixer; this is good for mixing cold cold Lake Ontario water with hot water from your tank. The k-2443 is SO short it's invisible. Your shelf projects the distance you want it to. (Another product the k-2440 is a ready made shelf. Another product is a ready made medicine cabinet, into which you may put this invisible faucet.) Web search "K-2440" "K-2443" outside Kohler's web site. When you open the PDF documents you can see how simple the faucet is, and therefore how easy it is to install in any shelf / tablet / support / that you design to fit your space. It's modular.

Aquabrass has a Blok faucet. It is also a shelf with a faucet integrated into it. The shelf is made of Corian, which cuts like wood, so you can reduce the dimensions of the shelf if you want it to be smaller. Several versions.

Dornbracht has a Corian shelf with a faucet integrated into it. Elemental Spa. Two versions.

I know many companies that would have no problem cutting any spout down to a smaller size and rechroming it for you.

Hth