Alliance are a serie of different mods. On the Star Wars GC, you can play the civil war Empire vs Rebel era + Black Sun and soon the Republic and CIS.
The Supremacy, the Raddus and even the MG-100 StarFortress SF-17 bomber are ready and there will be in the next upgrade. This video is a funny battle from skirmiss where the AI uses the Supremacy against me. It gives you a good idea about how you will need a lot of very powerful units if you want defeat it.
Oh my gosh! That thing is HUGE!
AWESOME!!!