Captainhook told me it's impossible to switch from Scrypt/PoW to X11/PoS but i proposed a plan to make brand new iCoin PoW/PoS and current iCoin holders can exchange old Scrypt iCoin to X11 iCoin.
Yes that would probably be the best solution. I believe Particle is going to do something similar, have an exodus address where you send your old coins and the system sends you corresponding amount of the new coin:
https://bitcointalk.org/index.php?topic=392804.msg6865589#msg6865589