I agree with archangeli. Any brush you CAN find an equivalent to in the art store, why not go for it? The biggest reason I don't use more art brushes is they tend to have longer handles than I like for makeup brushes, and I don't want to have to saw off the handles of my brushes.

Also agree with buying a blush/powder brush meant for makeup.. as a painter I don't see what purpose this brush would have for art.. but I could be wrong, there might be such a thing available at the art store :P