Rumor is that SpaceX is negotiating a large deal with Toray to access carbon composite in very large quantity, but the Company is not yet ready to make the announcement. "Toray is one of a number of suppliers we work with to meet our carbon fiber needs for Falcon rocket and Dragon spacecraft production, and we haven’t announced any new agreements at this time," "As our business continues to grow, the amount of carbon fiber we use may continue to grow."

As we predicted earlier this year the Aerospace industry including SpaceX is betting big on carbon fiber composites, which will increase the capacity of its future rockets and will allow SpaceX to get people and supplies into space.
It is not immediately clear exactly when, and in which launch vehicles, these lightweight composites will be employed by SpaceX.
But the company is not alone in its interest—NASA, BOEING and other aerospace companies have been experimenting with the materials because of their potential to increase the amount of payload that can be carried by a rocket making it lighter and would eventually will lower overall manufacturing cost.

The scale of the deal (~ several Billion Dollars...) is significant not only for SpaceX but for the entire industry as it may exercise pressure on manufacturer to lower the cost of carbon composite by massive usage in the Aerospace industry.
SpaceX might be considering using carbon in its Mars Colonial Transporter rocket. This could be a very large rocket. The company plans to eventually use to transport humans to Mars.

SpaceX is already far along in the production of its Falcon Heavy rocket, which is based on the Falcon 9 core stage.
The first stage of the Falcon 9 rocket, which SpaceX has successfully been landing this year, has tank walls and domes built from an aluminum lithium alloy like traditional rockets.
Carbon fibers present desirable qualities such as high tensile strength, low mass, high temperature tolerance, and low thermal expansion. This has made them very popular with aircraft manufacturers, such as Boeing and Airbus. Toray, a Japanese chemical firm, is a leading provider of carbon fibers to airplane manufacturers.

Libra6 Management, Corp. invests in Cleantech and alternative technology and is currently leading an investment in California Carbon Industry

California Carbon Industry, Inc. is focused on designing, developing, and manufacturing advanced carbon and composite materials and products for use in the aerospace, automotive, marine, art, furniture and construction industries.