+1 for udp tunnel with static key
This is really show stopper that you need another device to make openvpn p to p tunnels. Currently if you need real l2 tunnel without any ip there is no good way to do it.

I will say that openwrt. I dont know how well it work with routerboard but that openvpn implementation in routerOS is more bad joke than anything what you want use. Does anyone know that is openwrt supported on RB2011? I tired several weeks about one year a go routerboards (3 different model) and af...