Well, speaking strictly as an amateur, I personally don't see why it would present a problem, as long as the roots of the vine crops are kept a sufficient distance (probably 6 to 8 feet) away from the young trees to avoid competition for nutrients and especially water, and as long as you manage the top growth of the vine crops so that it doesn't get up into and smother out the young trees.

Actually, I would think that any type of crop grown between the rows, allowing adequate clearance around the trees, would be beneficial since it would act as a cover crop. Better than weeds, anyway.