Is it possible to extend the reach of a PN532 NFC/RFID shield? I am working off an Arduino Uno with an AdaFruit PN532 NFC/RFID shield. The goal is to have a shoe box, with a false bottom. Under that false bottom would be my prototype, which I hope will be able to detect any MIFARE tag that is in the box, above the false bottom.

The range obviously for these devices is practically touching, but I was was wondering if there is anyway to extend the reach of the NFC/RFID shield, so that the entire false bottom of the box could act as that antenna.
I suspect not. NFC is designed for short range for privacy reasons. Some RFID systems have longer ranges (a few meters). They work by using an electromagnet to create a switching magnetic field. The RFID/NFC chip takes power from the magnetic field and then modulates a signal onto it, which the sensor detects. In order for it to work the chip needs to be close enough to get as strong enough field to power itself, and to modulate that field.