Poking at the RPG Maker VXAce map format.

[MechanicalPen]

With the default scripts, probably not, but I have not been able to find the place where the scripts load in the five tileset_names of a tileset so I cannot say for sure.

Edit: here's something interesting.

Code:

#--------------------------------------------------------------------------
  # * Get Tileset Image That Includes the Designated Tile
  #--------------------------------------------------------------------------
  def tileset_bitmap(tile_id)
    Cache.tileset($game_map.tileset.tileset_names[5 + tile_id / 256])
  end

We might be able to rewrite class RPG::Tileset to save more than the 8 tileset_names