How it works:
The player in config sets ip or domain of dedicated server, that runs file hosting script
It allows to player to be fox or ultra-detailed steve on any server he plays.
Any player, who uses this mod and connected (using config file) to the same model hosting server, will see another player's model.
It's very useful

If you don't think so, then i want to request access to source code to try implement this idea

Actually we have thought about this before, the problem is players cannot switch between different models as freely as now, which in my opinion is really important.
But having another model loading method is still a good idea. Due to time limitation, I'm not planning to implement myself. If you are willing to help, just create a fork and go ahead.

And, as a feature, this improvement allows anyone to write a "model hosting server" in any programming language