Would it be possible to use a simple beacon (the least expensive one) and codes its
firmware to scan for specific iBeacon uuid and only if detected advertise an iBeacon packet
for several seconds and than stop?
Proximity beacon firmware does not allow to scan for BLE packets.
This is a technical problem because scanning consumes much more energy than advertising and this would significantly decrease battery life. Periodic scanning is not a problem on smartphones because they are recharged daily by the users. Scanning is possible on LTE Beacons which have rechargeable battery and are user programmable so scanning can be precisely controlled (for example in business hours only or when device is in motion).