FriendlyARM releases a new SBC with two ethernet ports, one of which is Gigabit for $29.
OpenWrt supported.
link: http://wiki.friendlyarm.com/wiki/index.php/NanoPi_R1
link: https://www.friendlyarm.com/index.php?route=product/product&product_id=248
UPDATE:
Careful, while new sunxi devices are generally relatively relatively easy to add support for, it doesn't materialize out of thin air either (read, at this moment it is not supported by OpenWrt).
What a pity, as it looks like powerful and cheap hardware.
Very suitable for my type of apps, like hotspots.
The NanoPi R1 already supports OpenWrt.
Downloads pre-compiled images here: GoogleDrive
http://wiki.friendlyarm.com/wiki/index.php/How_to_Build_OpenWrt
That is incorrect, the vendor might offer their own fork based on OpenWrt, but OpenWrt does not support it yet.
They probably need to rename their fork if OpenWrt is a registered trademark and they are insisting that they do not need to work with their upstream in what looks like an attempt to be considered upstream themselves.
Kind of odd when vendors do this. They fork but keep the same name..
As of tag 18.06.2, the official OpenWRT does not support NanoPi R1 (Allwinner H3).
The OpenWRT only support Allwinner A1x, A20/A3x and A64.
The manufacture's fork is heavily modified source code, and have many compatibility issues with other packages.
The Allwinner H3 looks really good but it is too cheap, support it now may cause market/price turmoil. Years later, when famous brands released more advanced devices, the support of Allwinner H3 may be possible.
Allwinner H3 SoC is supported by OpenWrt.
Most of the OrangePi SBC are based on Allwinner H3 and H2+ SoC and are supported by OpenWrt as of tag v18.06.2.
OrangePi PC: https://openwrt.org/toh/hwdata/xunlong/xunlong_orange_pi_pc
The xunlong_orange_pi has only one 100 Mbps Ethernet, so it is supported by the OpenWRT.
For now, OpenWRT would not support any cheap dual-ethernet Pi(s).
The only exception is GL-MT300A which only has two 100 Mbps ethernet, rather than 1Gbps+100Mbps.
xunlong_orange_pi_r1 has dual 100M Ethernet and is supported by OpenWrt.
Also, ESPRESSObin has multiple gigabit ethernet ports and supports OpenWrt. And so does many x86 boards with dual or multiple ethernet ports.
I don't see any reasons for OpenWrt not supporting these boards.
This looks like exactly the sort of device I was hoping to find a couple years ago when I upgraded my LAN and switched fromm DD-WRT. If I buy one now looks like, given that there's already an OpenWRT fork for it, there may appear soon full support under standard OpenWRT, right?
Only if someone with the board in hand and the skills, time, and desire to port it.
There is a difference between "should be straightforward" to going through all the steps to get it working, get the code into an acceptable form, and get it accepted into master. If you consider "standard OpenWrt" meaning "release" images (as opposed to "snapshot" images), then there's likely going to be months until that happens, as the release branch for v19 has just been "cut".
another problem with nanopi-r1 is that it's expensive, $29 is the base price, then you must add at least a SD card, which is $8 or so, and power supply, and shipping is $8, now it's about $50 before you can boot it up. If you want its eMMC version plus a little more memory, that's another $10.
What's a cheaper device with similar size and capabilities (Bt4, mediocre WiFi, 100mpbs + 1Gbps Eth, 512MB-1GB RAM & 4x Arm Cortex-A7)?
Please use this topic only for discussions regarding adding OpenWrt support for this device.
For questions like "Which device should I buy? Which device is better / cheaper / faster than...?" please open a new topic in the hardware section of this forum.
I have board in hand and ready for help with test.
I'm new in development but will do all i can 
Armbian already has a build for the board which is marked as mature software, so it looks like there should not be major problems with the drivers in OpenWrt.
There is now the NanoPi R1S-H3 and NanoPi R1S-H5, and the R1S-H3 is $20 USD. wooooooooooooooooo
https://www.friendlyarm.com/index.php?route=product/product&path=69&product_id=274
The H5 will be different for sure, but the H3 is going to be nearly identical to the R1 with just a few DTS changes. I will probably buy one but I don't think I have the time to pick through their code and mainline everything into OpenWRT.
I am not impressed by Nanopi R1S, FriendlyWRT, a fork of OpenWRT does not support TCP BBR
