Would it be too hard to add non TCP traffic tunneling? This already supports DNS traffic through the tunnel but I wonder it is feasible to tunnel all kinds of traffic (UDP and ICMP mostly) through it?
By the way, (open-)ssh itself supports a tun/tap VPN mode (-w I believe) that creates actual network interfaces on the two endpoints, and thus can transport any IP traffic. It needs to be explicitly enabled on the server, and needs kernel tun/tap support, which is usually missing on VPSes that don't let you run your own kernel (modules).