So, I just got around to finally get my setup straightened out.
Now the (open, Free, unlimited!) Wifi is first NAT-ed and then all requests to port 80 ( web servers ) are mangled into privoxy ( set to accept intercepted connections ) which then forwards them into the tor-relay ( open relay, no exit node, 40-150KBytes bandwidth ) .
The net result? Free, anonymous wifi. And horridly slow due to how tor performs at the moment.
Well, it works. All other things are offered through freely, if someone has a VPN they will have a solid performance. Their torrents will load faster than their websites even ;)