TL-WDR4300, AR8327, Q-in-Q and OpenFlow?

I'm interesting in using OpenFlow 1.3 (with Faucet SDN controller) on OpenWrt. I currently have a TL-WDR4300 router which I have tried using with OpenVSwitch and the Faucet SDN controller. I would need to use Q-in-Q or stacked VLANs but the switch (AR8327) discards VLAN tags it doesn't recognize which means you can't have trunk ports without preconfiguring the VLAN tags in UCI.

Is there a way to use Q-in-Q or stacked VLANs on TL-WDR4300 (AR8327) that I'm not aware of?

Or are there other routers with switch chips that support Q-in-Q
or stacked VLANs? If that's not the case then I would need to buy an external switch with Q-in-Q support. Any recommendations?

I think that swconfig is in conflict with Open vSwitch and maybe that's your problem

What conflict are you referring to? There shouldn't be any since Open vSwitch AFAIK doesn't support the switch chip (or swconfig). That lack of support is also the reason I would need to use stacked VLANs which unfortunately AR8327 doesn't seem to support.

from brief datasheet:

Full VLAN support including QinQ and VLAN tag insertion and removal, with IVL and SVL

full programing guide

UCI uses swconfig to create vlan interfaces, I think a developer with experience on ar devices can help you, maybe @981213