I'm not going to LD_PRELOAD some random library into my SSH process, and I'm definitely not going to export LD_PRELOAD as a global environment variable.
Couldn't this be setup with some kind of virtual IPv4 interface that routes to your IPv6? I guess you'd need some kind of driver to add the prefix.
Yeah I'm pretty sure with some simple virtual network bridges and routing rules a 4-to-6 converter is plenty possible without touching the actual processes.