We tried a setup like this, but din't really get too far into the game because someone had to leave in the middle of turn 3, so I can't how well it would have worked for a whole game but things seemed to start ok.
Each army was 200 points and had a 2 x 3 deployment zone. Axis at one corner, Aliied, in another and the SSU at the center of the opposing long side.
| | 9 Squares
I suppose you can scale this up for bigger maps and larger armies.
What was the game objective you used?
I've played a similar "King of the Hill" setup in AT-43 with the hill in the middle of the table, and Victory Points awarded at the end of each round for the army in possession of it. Once the carnage began, though, the focus would shift to the army deemed the greatest threat and they'd start to get hammered.
I'd be curious to learn how your games turn out, since there are often three of us that gather to play.