I think the question comes down to why? You can get a high end purpose built router, for probably the same cost if not cheaper, more power efficient, and likely much better supported based on the lack of posts in the x86 forum.
Seems like x86, be it minipc, laptop, or full desktop would just be more headache than it is worth.
If you need the processing power to route enterprise grade traffic, then you likely should be looking at purpose built enterprise hardware. Kind of the old addage "you never get fired for choosing IBM" If you home built router falls flat on it's face and knocks out an enterprise grade network for any amount of time, heads will roll. However if you Cisco or (insert other big enterprise router manufacture here) router goes belly up, and you did everything in your power to ensure it was configured properly, kept maintenance/support agreements up to date, and got the vendor involved ASAP if things were over your head, you have a much less likely chance of your head rolling.
if you use openvpn you can use the full computing power of AES Encryption engine on many x86 cpu. with the Pcengines APU2 platform you can have more than 100mbps raw openvpn throughput at very low cpu load ...
all highend router lack this feature , for a reason - the companies want to sell their own overpriced buisness vpn platforms.
apart from that you can use the latest 802.11ac minipci-express wireless lan modules from qca98xx and qca99xx family and of course all 802.11n and 802.11abg atheros chipsets.
so you can build a pretty powerful machine ...
the device you suggested may work, but have a look at the pcengines apu2 platform, they are very affordable, designed in switzerland, made in taiwan, top quality and very easy to use with dd-wrt and also many other operating systems
I have took a Dell Studio 540 motherboard and slapped a good 350W power supply inside a spare micro ATX case. Had a gigabit PCI Realtek card. 4GB ram. It will soon have a 20GB M.2 boot drive for dd-wrt. Has a duo core E7500 cpu right now but I do have Q6600 processors laying around.
I built this about 3 weeks ago since my old Conroe 2.6Ghz motherboard died on me. Its much cooler running system. Plus it has a gigabit onboard Ethernet port so it saved me from adding another card. Has 10 USB ports. So I made it into a NAS server and just today I found out how to mount hard drives onto the 3 available SATA ports removing the bottleneck going through USB 2.0 ports for NAS. This system is constantly getting more features built into it and it only cost me $26 for the board since I had everything else in the closet over the years. This is better way of going about it than possibly bottlenecking your connection to the internet using USB 2.0 adapters if you have a connection faster than 100mbps. The way I did it I have future proofed for better speeds they may bump me up to down the road.
Posted: Tue Mar 27, 2018 16:24 Post subject: Here's How I did Mine
I know this post is old but I thought I would add my experience.
I have built DD-WRT X64 on a HP 2540p laptop which has a Intel Gigabit ethernet port on board, but which also has an ExpressCard 34 port. I used a Realtek 8169 based Gigabit card in this port and managed to get it all working, including VPN, PBR and MAC assigned DHCP leases.
I know this is nothing special but there are many laptops which have Expresscard functionalty, I know of HP 2540p, 4330s, 4530s, 6730B and DELL Latitude E6430 to name a few, all of which I have access to as I fix PC's for a living.
The 6730b only has Fast Ethernet though!
So my new router is destined for VPN use as my 150Mbit ISP line only sees half or less that that with my Linksys 3200acm router.
I only registered to post my experience. I wanted a low power usage system, and the laptop fitted the bill.