A wall mount faucet with a pull down sprayer would require installation of the hose in the wall cavity, which is a complication in and of itself, which is why you aren't finding them. There was a poster in these forums several weeks ago who presented his design for something along these lines and it was clear from the comments that it adds a level of complexity many people don't want to deal with, particularly if the installation needs maintenance.

Wall mounted pull-down sprays don't necessarily retract into the wall.

As for a faucet that goes low into the sink....

worthy- I've never seen that design. Can't say it's my favorite esthetic, but it would do the job.

I agree with @kudzu9 that the setup of an external spray is not what I'm after. So how about the second option?

Try looking at wall mounted laundry or utility faucets. They typically are longer and have more wall mounted options - some with sprayers as well.