Guys read this, seems like a fun thing to do:
http://www.ex-parrot.com/~pete/upside-down-ternet.html
And if someone knows hoe to do it with routeros please let all us now.
Best
Jorge Boardman
use external squid server. then set a filter for the user through nat then forward to external squid. Let me know if you need any more info.
I tried it with my family. They all have dsl service from us. Pretty funny.