It's available in seed form from Devil's Harvest Seeds (breeder). I don't know what the stock would be like at any of the seed banks, though.I was thinking of a cut today that I stopped looking for years ago because it was clone only. It was called Casey Jones. I still don't think anybody has it in seed form; maybe I'll have me a cup of hot tea and look later.....
I remember looking into this years ago since I always suspected that Pineapple Express was a cross between Pineapple and either Trainwreck or Casey Jones but the true origins of the PE are some ancient secret, I guess?