Mass producer is a building that increases the number of trees bushes etc that you can have in your village + it increases the amount of gems and xp you gain from removing new obstacles that grow in your village, it unlocks at th8 and has 3 levels :
LVL1: costs 250,000 Elixir, increases the capacity from 40 to 42 and increases avrage amount gems that you earn from 2to3, increases the zp that you gain for 20% and takes 2 days to build (XP: 250)
LVL2: costs 400,000 Elixir, increases the capacity from 42 to 46 and increases avrage amount gems that you earn from 3to3.5,increases the xp that you gain from removing obstacles for 25% and it takes 3 days to build (XP: 400)
LVL3: costs 700,000 Elixir, increases the capacity from 46 to 50 and increases avrage amount of gems that you earn from 3.5to4,it increases xp that you gain from removing obstacles for 30% and it takes 5 days to build (XP: 600)
SECOND IDEA:
The dark bow is not a new defensive building, you can upgrade one of your current lvl4 xbows to a dark bow, Dark bow has 2 modes and it can only attack ground units(Notice: you can change from Dark bow to lvl4 xbow too)as I said it only has 1 level:
LVL1: Costs 150,000 Dark Elixir and 1000 Dark Elixir to recharge (modes: Heavy shot: It does 450 damages per 3 seconds and stuns the target for 0.1 second, Light shot: it does 125 damage per second) The range is same as normal xbow
THIRD IDEA:
Dark Tower: This Building Shocks troops, but troops keep moving (what does it mean?!) when a troop is shocked it cant attack for a while!,this building has 8tiles range and it has 3 levels:
http://i.imgur.com/dkOAF7r.jpg
LVL1: Costs 750,000 gold to build and 200 Dark Elixir to recharge (it shocks troops for 0.5 seconds) it does 15 damage per second(1.5 radius)
LVL2: Costs 2,250,000 gold to upgrade and 350 Dark Elixir to recharge (it shocks troops for 0.7 seconds) it does 20 damage per second(1.5 radius)
LVL3: Costs 3,750,000 gold to upgrade and 500 Dark Elixir to recharge (it shocks troops for 0.9 the seconds) it does 25 damage per second(1.5 radius)
All of this ideas been mantioned I just refined them and made this thread thank you for reading my ideas hope u have enjoyed it and sorry for bad english!!!