I second the shout about allies? DO they count as a seperate army even if clearly modelled to be allies, eg: imperial guard made up from Gorkamorka Digga models to ally with my orks?
Also in a similar veign where do counts as units stand? For example i have a unit planned for my orks of tinboys, i planned to use the rules for thousand sons squads to represent them in apocalyse games, likewise i was plannign a "Giant squig and babies" using the tervigon rules.
I probably won;t get these units ready in time but it's good to know one way or another.
I'm in again this year, Probably still orks and i'll use either my inquisitor warband or space marines as my second army.