I am wondering which US airports allow you to re-clear security after an INTL arrival to go airside without an onward bp? I ask as this could be useful to visit lounges for showers and/or a quick snack.

ATL E and F come to mind, after clearing CBP and exiting baggage claim, you can head thru the TSA checkpoints dedicated to transit passengers to access airside. Airside 1 at MCO works this way: after CBP and collecting bags, you re-check them to the domestic bag claim (if ending in MCO) and clear TSA to take the train to the main terminal. This is because there is no path for INTL pax to access the trains without mixing airside, contrary to airside 4.

ORD, JFK, EWR, LAX and SFO do not allow this and I don't think MIA does either. I therefore think it's a good idea to gather a list of airports that allow what I describe above.