It's not a router platform, but I thought this was an interesting development.

EdgeCore is apparently contributing 3 Access Point designs to the OpenCompute project. 

http://www.businesswire.com/news/home/20160309005481/en/Edgecore-Networks-Brings-Open-Networking-Access-Network

One of the designs, a 802.11ac 3x3 MIMO design, looks to be based on this: 
http://www.edge-core.com/temp/ec_download/1448/ECW7220-L_DS_20150916.pdf  (there is an outdoor 3x3 and an indoor 2x2 as well)

Are there any thoughts as to the feasibility of using this as a basis for make-wifi-fast?

Regards,
  Kelvin