Need 2-3 large ones for starting bokashi. Then some smaller ones for making a super bokashi compost mix of minerals, bio char and other goodies.  (biochar talk happening in permies

An article discussing large scale bokashi can be found at http://themanicgardener.com/2011/03/large-scale-bokashi-1.html
Unfortunately only a picture and no plan for building these bins.

If that scale is not large enough then check out this video at 
Here they builld a giant bokashi heap of 500 (metric) tons of "stromest" (straw and manure mix), "grasafval" (wasted/garbage grass) and "drijfmest" (liquid manure). I am sure they get a hefty discount on those huge bags of bokashi bran