Ooooh, spreadsheets.

I see the potential nightmare in the accounting of a rebel state, even for a fairly small secession.

I take it a secession could result in a semi-stable splinter state (assuming the new state and one they're rebelling from reach a point where they are too powerful/unwilling to absorb eachother in a war). If so infrastructure improvement is likely to become a concern to the rebels after the defeat of any immediate threats (i.e. large loyalist armies).

Maybe as far as the armies go we could use the same rules we currently have for how many troops a House are entitled to. If the rebel armies fall below this point they can retrain or recruit troops to top off. Sackings, ransoms, etc. would allow one time expenditures on troops and infrastructure.

Assuming a successful secession, available money for infrastructure improvements could be figured out with a similar system, or maybe just give the secession leader the ability to prioritize, say, 1 building twice a term for every 4 settlements he owns (the exact ratio used would likely need tweaking ,trying to strike a balance between allowing the new state to spend some funds on buildings without favoring them so the real empire is getting cheated out of florins).

It would still add work but wouldn't be as hellish as having to constantly monitor wages, corruption, income, etc.