I've been toying with the idea of a new construction asset, the Chapter House.

Chapter House: Chapter houses are the mustering points for religious orders. They can be built in any province of a domain, in which the regent owns a temple holding, but are limited to a total of 10 levels throughout the entire temple domain. Each temple domain can support only one religious order. Chapter houses allow a temple regent to muster unique chapter units unavailable to other regents. A temple regent can muster a chapter unit in a province with a chapter house, if the regent controls a temple holding + the chapter house levels in the province, equal to or greater than the GB cost of mustering the unit + levels of opposing law holdings in the province. Chapter units must be bought and maintained normally, and the regent can only support twice the total chapter house levels worth, in unit GB cost. Chapter Houses are protected by any temple holding fortifications of the province they are built in.

COMMON CHAPTER UNITS
Unit Type Melee Missile Def Hits Mv Mrl Cost Special
Fanatic LtIrr +6 - 10 2 2 +4 3 GB Berserk, +2 charge
Order Foot Soldiers MdInf +4 - 14 2 1 +4 2 GB +2 melee vs. Irr & Pike
Order Knights HvCav+ +6 - 16 3 3 +6 6 GB +4 charge
Templar Knights HvCav+ +6 - 16 4 3 +8 8 GB +4 charge, Toughness, Order training*

Excuse the formatting - but you should get the idea.