We starting playing with Malbec years ago, both in our "Arsenal" Bordeaux blend, and our "La Battalla" Loire inspired blend. Malbec acts as a perfect foil to Cabernet Franc, filling the middle of the wine in with chocolate, velvety goodness.
My mother-in-law particularly loves Malbec, so making a bit on its own seemed a good way to ensure additional favor. We have a small amount planted on our Mae's Vineyard, and source the remainder from the steep Castellano vineyard, which grows exceptionally dense, ripe Malbec.