12 V to 5 V with highest current possible
Is there a switching regulator out there that will do this


It's called a buck regulator and some can be as high as 95% power efficient. That means, with 12 volts and 14 amps on the input (a power of 168 watts), the output power could be up to 160 watts or 5 volts and 32 amps.

Bearing in mind that shopping questions are off-topic on this site, so there's no point trying to recommend one but, if you find one that looks good for the job, I'd be happy to see if it might fit the bill. You'll need to look for a synchronous buck regulator i.e. one that has an active flyback MOSFET instead of a regular diode.