Very ambitious idea...

... which I would like to implement but I have no skinning, terrain, trigger or modelling skills whatsoever. And I'm not asking for a team rather than just running this idea through you. :)

Anyway, there're three teams with three players each - builders, bandits, merchants. There's also a fourth team with just one person in it, this person makes creeps, just to make the game more interesting.

BUILDERS

These guys are at the top side of the map, the bottom left and the bottom right - they have two smallish areas surrounded by walls where they start. These represent the safe area (enemy builders can enter [military units only :) no building units], merchants can enter, but bandits and creeps can't - save under very special circumstances), the semi-safe area (this can be bombarded with bandits' siege and attacked by flying creeps but otherwise the rules are the same as the safe area) and the outside world (anything goes).

Builders aim to make the best cities (luxuries and decorations increase your funds, wide streets mean that more units can stay in the safe area). For a builder's victory they need to either:

a) kill all the other builders' cities
b) kill every bandit unit
or c) max out the gold counter at the top of the screen

MERCHANTS

These units are very vunerable, they have a safe base area where they can make more merchant units [for a high price], but most merchant units can't attack, so they're very vunerable to attack by creeps or bandits. So they may decide to enter into the service of a builder, so that they are protected from attack in exchange for selling items exclusively to that builder. Merchants also sell mercenary builders to builders, the prices for these are high but are given manually, so haggling can take place.

For a merchant to win they need the most money (they lose money every time one of their units is killed) when a builder wins.

BANDITS

These units are never attacked by creeps, their aim is basically to waylay the merchants and builders - they get money for every unit they kill. At the end of the game (when a builder wins) they need to have the most money out of all the bandits.

Bandits can enter the safe area of a builder's town under ONE circumstance (and even then they can't attack the main capitol or any worker units) - if they buy an expensive worker unit (VERY VERY expensive) which can basically start a siege of a town. When this happens, the other bandits act as allies to the besieged, the bandits sieging the town lose any invisibility magics and night falls (and it stays night until the siege comes to a conclusion). When this happens they can enter the safe area of a builder's town - a siege comes to a conclusion when every building made by the worker is destroyed (these CAN be attacked by creeps to prevent farm-hiding) or until the builder performs a command (maybe from a menu from the main building in his town?) that automatically destroys all of the siege units the bandits have (and the worker), pays for the price of them (and the worker) and gives the bandit 75% of the remaining resources.

CREEPS

The creeps have no victory condition, if the player leaves or is absent from the start, the computer takes over these.

GRACE PERIOD

This lasts the first few minutes of the game.

In it: builders CANNOT train military units or move workers outside the semi-safe area.
Merchants CANNOT leave their base (although they can produce what they have to sell)
bandits have only one unit, an invunerable, invisible scout unit with no attack - after the grace period other bandit units appear and the scout dies.
creeps do not respawn and have no attack.

I may be able to implement some of the main ideas i drew out from your ideas into my map, thanks for ideas. Btw you are a good ideaer maker