I have spent weeks going in circles on this issue because the sink run in my old house is just 21 inches deep, including counter overhang.

Faucet direct allows you to search by width (the front to back measurement).

If this is be your main sink, the possibilities that come immediately to mind are a fireclay apron front sink or a custom (copper, soapstone, etc) apron front sink paired with a wall mount faucet. I'm not sure how the edge between the back of the sink and the backsplash would look or end up finished--chaulk? A drop in or under mount would end up too small to be very useful, I think, even if you find one.

If this is a prep sink then it should be somewhat easier to find something that would work, I think.

(I am currently leaning towards a kohler stages 45 with faucets mounted on each side at the back corner, but I have three more inches to work with than you do. If my contractor says that's a no-go because the stone can't be cut that small in the front and back then I think we will likely bump our sink cabinet out to make just that cabinet standard depth)

Hello! Just checking back here now. Thanks for your thoughts. Went to HD and there are relatively shallow sinks. We also may do a bumpout and wall-mount the fixtures. They had a 16" sink on display and I think even that would be OK (it's our main sink but that should be sufficient).

Here's the sink I'm planning on:
Elkay offset drain, shallow sink