I've got no designs on doing this in the near future but have finally decided to seriously entertain the idea long-term. Between my kitchen and living room there's a half-wall (capable of bearing a load) with a shelf that's approximately 8 inches wide and 6 feet long. Since we moved in I've thought it would be a novel place for a tank but always passed the idea off. So I was thinking an 8x12x72 tank. built-in to the walls. Is this feasible (for the fish) or would it just be too narrow?