Set frame by plugin

[NiLSPACE]

I believe there is: http://mc-server.xoft.cz/LuaAPI/cItemFrame.html

Or at least if that's the frame that you mean.

World:ForEachEntityInBox(cBoundingBox(X, X, Y, Y, Z, Z),
 function(a_Entity
  if (not a_Entity:IsItemFrame()) then
   return false
  end
  tolua.cast(a_Entity, "cItemFrame"):SetItem(MycItem)
 end
)