Ok now here is the solution to the random data issue:
Every forger creates a very large random number. He hashes this number and adds the hash to to block he is forging.
 
He than creates a transaction that will reveals this random number. This transaction in not yet beeing pusblished to the network. Instead this transaction is beeing sent as encrypted arbitrary message to the 10 previous forgers. These 10 previous forgers decrypt that
 arbitrary message and check the random number against the hash in the blockchain. When everything is ok every previous forger creates an arbitrary message that states that he recieved the correct transaction (these 10 arbitrary message will be added to the blockchain).


After 100 blocks the transaction that reveals the random number is beeing published to the network (and added to the Blockchain).

Now the last known 100 random numbers are hashed together to seed the random function (Only those random numbers are used where short after creation most of the previous forgers stated they have received the revealing transaction).


It's just that easy!