This idea goes against several concepts, as such I don't give it many chances.
One, food is very intentionally localized. It is one of the limiting factors for large realms, and a centralized treasury would defeat that purpose.
Two, gold is given to characters, not positions or places.
Three, this only fits for highly centralized government types.
Also, according to the tax reports, which states, and I quote, "The crown has received 205 gold tax income thanks to a realm share of 10 %.
In addition, the realm made 430 gold from other sources (fines, etc.), bringing the crown's total income to 635 gold."
Certain positions do receive gold. I remember the same happening for the other council positions, at least before the new estate system took effect. I'm not sure if the separate positions each get a share of gold anymore or not.
