I'd go for the standard set...
Flak panzer (modeled like a bomber with driver & gunner)
Jeep (see FP with not too powerful gun)
Some sort of tank (don't care which)
And naturally a destroyable garage at each field so that FPs & jeeps don't prevent capture.
Mind you, it would be kinda neat to put the garage NEAR but not on the base.
That way people could ferry supplies to bases with a short drive (using trucks). This'd give the heavy fighters a strat target and let people manually resupply bases (but not without risk)
~Lemur