So, we have a guild for weapon and armor making. I figured it might be helpful to have a guild that keeps track of all of the realm's finances, plans projects, and allocates funds and such. For example, if in the future we want to host an event, the guild would figure out all of the costs and how much to spend and charge. When we're not having events, they can review the money the realm has and brainstorm possible projects [walls, weapons, armor, etc.] to present to regional councils or the Conclave [if the project is realm-wide] for permission. They wouldn't be allowed to spend money without permission, and if the project is going south it can be discontinued with due process.
Does this sound like a reasonable suggestion, or an unnecessary complication? I suppose it wouldn't matter if nobody wanted to do it. Although it could simply be composed by all of the realm's scholars and retainers, plus anyone else who'd be willing and helpful.