I'm not so sure that the dye would come off on your clothes. When I had my seats repaired in my Barracuda, they sewed in new portions that were damaged and spray dyed cloth portions that had faded. I've used vinyl dyes in the past with good results, although they did have a tendency to show wear within a year. The dye that the upholsterer used was called COLORBOND.
http://www.colorbondpaint.com/