In the "6-player Addon" rule book you can download from Hive there is an extended Scenario that combines most of the Campaign Scenarios in the game.
Also you can try out the Arena (PvP) Scenarios of the game, you just need something to track Victory Points (you can use any tokens you like). There are also 10 common Action Cards missing, but you can play the Scenarios without them. If you start playing the Arena Scenarios, there is one extra in the "Scenarios" section.
We will also be releasing a new scenario that combines Centauri Saga with Cosmic Pioneer by the end of this week.
Of course we have started a competition for the creation of even more scenarios. The submission process will open this week too. :)