My friend wanted to monitor food amount (weight) in 400 feeders on one farm heh)
Your best bet is WiFi or BT or design non standard protocol translating and forwarding spi/i2c etc.
My other engineer friend designed some kind of device transferring data over one wire in large warehouses.
That was inhouse company job and I know it is some kind of common standard just look it up.
I found this info:
https://www.maximintegrated.com/en/app-notes/index.mvp/id/1796