This is my biggest so far (I'm red):
Eventually yellow quit and the computer went haywire, so purple attacked him and the rest was history :P The whole game I was building up enough of an army at my borders to attack both of them.
Then decided to jump into Australia:
The largest army of mine I got a screenshot of was 372.
I'd have still beat them if AI hadn't took over yellow haha.
Post some screenshots of your biggest army!! :)
Should point out, this was a fixed card trade game, not progressive. I only play fixed.