I noticed on my "Edit Nation" page that there wasn't any "You must pay bills before changing resources" or "You must collect taxes before changing resources", which I assume to mean that one can change resources without having done either. In that case, it seems like a group of nations could get together and form a cycling trade circle, where every 30 days all of them change resources. There could be a bill-paying set and a tax-collecting set, and in every 60 day cycle they would only have to collect 10 days of taxes while on the bill-paying set, and never have to pay bills while on the tax-collecting set.
Is there any reason why this wouldn't work?