I've looked but haven't found a way to get an AP to flash it's LED's so I can physically identify the unit.
Is there a way to do this with 1920's, 1925's, 2030's?
no, but there are other ways to id a particular ap, you can change the port speed on the switch port and that should change the colour of the LAN LED, or shutdown data but keep power flowing, or if you have the mac address you can identify the port that mac address belongs to, other then actually having to touch the ap, not really a way to do that.