Rye, wheat, or any raw grains will go well in a Saison. After all, it is a farmhouse beer, and whatever adjuncts they had around would go in to the beer.
One thing I'd suggest is resist the urge to make this a high gravity beer. The yeast will dry it out, even without sugar, but you're going to end up with a heavier beer if you have a higher OG. The classics will start in the 1.050 - 1.060 range and finish at 1.005 or below. The illusion of body comes from high carbonation, firm bitterness, and lots of yeast flavor.