chevrolux: Why not flash OpenWRT on to the Asus? Or actually probably better off going with DD-WRT as it is a bit easier can has a nice GUI.
Will allow VPN client & servers. Plus you can spoof the MAC address of the WAN interface for your Orcon connection. The RT-N66 has some pretty neat specs and would be a bit of a waste just bridging it to another appliance.
The DSL-N66U isn't quite the RT-N66U. From what I can find the Melin/dd-wrt support would seem to be experimental at best.
PPTP VPN support from dd-wrt also isn't 100% reliable, and is actually broken in the newer builds. It was doing my head in until I found a guide on one of the US VPN sites which told me the build where it was broken. Even with a working build I have't been able to establish a PPTP tunnel from a dd-wrt router to UnoVPN. I know the pptp passthrough is working on the Huawei because I can establish a tunnel from Windows and Android.
Last night I turned off the F/W on the Huawei and then moved the Roku to a DMZ to test whether packet inspection was causing the buffering issue on Netflix. It made no difference - apart from causing the Huawei to lose all its settings (yet again) - but the same condition happened where the WLAN and Internet lights blink in unison. I'm not sure I trust that the Huawei stopped inspecting packets, I suspect it just stops doing anything with the results.
The DSL-N66U would seem to have the raw CPU and QoS capability to rule out it causing issues with the Netflix streaming, and it is not likely to lose it settings so it has to be a step up from the Huawei :-)