tunbridge is a simple tool that steams data in and out of a tun network device.
I have successfully used it for a high latency, secure, simple, simple, simple VPN.
This ignores the appropriate ifconfig and route commands for the other end.
TMP=/tmp/$$ mkfifo $TMP /usr/sbin/tunbridge tun < $TMP | ssh -C $1 "/usr/sbin/tunbridge tun" > $TMP & ifconfig tun 10.2.0.99 route add -net 10.9.0.0/16 gw 10.2.0.99
I'm sure there is a better way to do this, but I could not get tinc or openvpn to work. It could probably be modified to operate with the tap device and act like a hub instead of a router.