Legitimate as in not a no name manufacturer? Nope, not yet.
This looks pretty good. Haven't seen anything else, though.
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can't even see one on ebay!
http://www.ebay.com/itm/USB-C-USB-3-1-Type-C-Male-to-Lightning-8Pin-Male-Data-Cable-for-Macbook-iPhone-/111651729099?pt=LH_DefaultDomain_0&hash=item19fef62ecb