802.11ac mesh hardware

What Miktotik hardware supports 802.11ac mesh? I´m looking for 802.11ac hardware with three radios so that the bandwidth is not halved on each mesh hop. What can be done with reasonable costs?

radio config

  • Mesh In radio
    Mesh Out radio
    Client access radio

Does the netbox 5 have a mini-pci express slot so one could add an extra radio to it? What would be recommended Mikrotik products for building such a mesh system?

Nasa link that shows how the bandwith degrades 34-45% with normal mesh networks
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20140011882.pdf

can you be more specifci bout application/goal of such intent ?
eg what you going to use ? BATMAN, HWM(&derrivartives), HMMP, MME ?
so far MME and HWMP support in ROS ~ working.
there was not much commercial(more medial, educationa, social, military, scientific and etc) applications, projects, but they are already there and for long/good.
maybe you ever heard for example about say “mesh potato” project(and similar 2 alikes)?

p.s.
http://wiki.mikrotik.com/wiki/Manual:Routing/MME
http://wiki.mikrotik.com/wiki/Manual:MME_wireless_routing_protocol
http://wiki.mikrotik.com/wiki/Manual:Interface/HWMPplus