Have you tried eBay?

Look on eBay, but don't just look for a "utility sink." Look for a "farm sink" too, because often those are single-bowl wall-mount sinks like what you're describing. Do a search on antique farm sink, then another on vintage farm sink, and so on. You will have to craft your search to leave out the bad hits--for instance, write -faucet (minus symbol plus the word faucet, no space between them) to prevent faucets from coming up in response to your search, and so on.

As of now, a search on "antique utility sink" (no quotes) brought up one sink that might fit the bill:
http://www.ebay.com/itm/Antique-Vintage-American-Standard-Utility-Sink-Slop-Sink-1960s-/230685429544?pt=Architectural_Garden&hash=item35b5ec4f28

And "antique farm sink" brought up a bunch of sinks, most of which have at least one drainboard, like this:
http://www.ebay.com/itm/Antique-Kohler-Porcelain-Farm-Kitchen-Sink-1930s-/250876792979?pt=Architectural_Garden&hash=item3a696c1093