[bombcar]

What probably could have been done (and kind of was done with NAT) would have been to move one byte from the port number to the address, giving us 256 additional “Internets” worth of addresses but limiting each address to 256 ports.

[p1mrx]

That's a good idea; it's called MAP-T.

Here's a NANOG presentation: https://www.youtube.com/watch?v=ZmfYHCpfr_w