O OpenVPN parece ter a opção --port-share
--port-share host port [dir] When run in TCP server mode, share the OpenVPN port with another application, such as an HTTPS server. If OpenVPN senses a connection to its port which is using a non-OpenVPN protocol, it will proxy the connection to the server at host:port.
Se o servidor da Web estivesse aguardando tráfego HTTPS em localhost: 49152, a configuração openvpn poderia conter:
port-share localhost 49152