I suggested the mirroring idea to CO for CIM2. They immediately rejected the idea out of hand as impractical.
Perhaps they felt there was insufficient demand for LHD, or more likely the were working on CSL and had no further interest in developing CIM2.
I still think that this is a workable idea and hope that Urban Games will give it serious consideration.
All visual content can be mirrored, except of course any text. That may be the most difficult part as it will also affect fan produced content that is not controlled by Urban Games. Only buildings and road vehicles would be affected as trains are not handed in the game (they can use platforms on either side), and will thus not need any modification.
