Four-Corners is an official skirmish map from Supreme Commander.
Each landmass has just seven mass deposits. On the plus side each land side is very easy to defend thanks to the small size of the islands and the predictable avenues of attack.
The small size of the map implies naval domination with prodigious air support is enough to win the game. Aeon have the big advantage with their hovering tanks but the other factions are not completely outclassed provided they can secure their island from harassment.
Against non-cheating AI in a 4-player game, at least one AI faction will fail to reclaim the wreckage at the front of the island and consequently will progress no further than T1 because of the AI's reluctance to deficit-spend on mass. Checking the score should make it obvious which AI faction that is (generally not Aeon). Turtling up to T4 experimentals to win the game might prolong the session to 1 1/2 hours maximum.