Did I forgot to mention "Proportions, 10 planet start?"
Actually it wouldn't take -that- long. One of the longest current KOTH games was 122 turns. Proportions 24 is pretty far in at 172, and that's with 5 players plus AIs.
The longest part would be killing the homeworld..force it to riot, though, and the game would be over soon enough.
Phoenix-D