Costus montanus is a high altitude Costus from Costa Rica that looks superficially similar to the plant in horticulture sold as C. barbatus (I found the real Costus barbatus in 2011). I have never seen it listed for sale elsewhere, or in cultivation in any US botanical gardens. It is most easily distinguished from similar looking Costus by the acute triangular ligules.
This seems to be a very difficult plant to grow. It is usually found (in nature) in cloud forest with continual moisture and high humidity but with very good drainage. I have had a hard time keeping it going in my greenhouse and only brought it to flower one year. Hardiness has not been tested, but I assume this species will only be hardy in frost free areas.