Has anyone heard of similar work done with smart light bulbs but for Meshtastic nodes?

Why would you put a LoRa radio in consumer-grade household electronics?

LoRa is also sub-optimal for payloads more than a few K in size and most ePub files are at least a meg...

Meshtastic / meshcore at this point look like a dead end of the development.

Take a look at HaLow if you insist, but in general if a bulb has esp32 then you could likely replace the module for one with LoRA capabilities.