Just the troop tree before you equip the soldiers. 3 branches: infantry, archers, cavalry.
You will be able to use ~90% of items existing in Perisno to equip your soldiers. Only very few of them (like unique items or Third Legion items) are blocked.
Unlike in PoP, you will not be limited to 9 slots. Every item you will put in a soldier's inventory will be taken into account. So if some of you don't like clone-like troops, you will be able to give your soldiers plenty of different items.
The upkeep of custom troops is flexible. 469-line script calculates a special multiplier that will affect the upkeep (it can either decrease or increase it) depending on how stats of the equipment you will choose will compare with certain "recommended" values. If you try to give you recruit the best items he can possibly carry, you will not like the result. It won't be worth it.
Still, when it will come to the highest-tier troops, then dragon scale armor, heavy full plates, best weapons and heavy chargers - they will all be yours if you want to maximize.
Finally, you'll be able to tell some of your lords (i.e. this is not a kingdom's culture, but an individual setting) to use these troops.
Just like you will be able to order your lords to use Freelancers as troops if you like them: