I'm intrigued by the idea of having one system do as many jobs as possible, so I'm playing around with an idea. Let me know if it sounds promising, or could use some modification.
Each player is a floating air-city. These cities are each a different color, and represented by a small player board. These boards are all placed on a larger sky board representing the height that they are floating at. There is only room for one city at each height, so the player boards are just set in order along that axis.
Each city produces a different color resource, which is stored on the city's board. Each city also has an air balloon that can travel up and down the layers of air to the different cities, and exchange resources with them. The resources of cities higher up are worth more than ones lower than them. The order of the city boards (from highest to lowest) also determines player order and priority. Each city also has unique abilities that can only be accessed by another player if his balloon is there.
After several rounds of oving and trading, players look at the number (not worth) of the resources that their city has collected. Then, players decide whether or not to anchor their balloons to the city they are at (in which place the balloon is placed on the city). Then the city boards are reordered on the sky board, with the city holding the most resources sinking to the bottom, and the one with the least rising to the top. Balloons anchored to a city travel with it, ones not anchored stay at their height.
I still haven't figured out the precise goal of the game (I'm thinking it will involve purchasing upgrades for cities using resource combinations), but I like how the game uses player boards as the main pieces in the game, and also uses them to determine player order, movement track, variable player powers, and economic power.
