There are lots of rumours about the Black List, but I would be very surprised if they were true.
If I were a recruiter, I would still give you another go, but I would be very interested to know exactly why you were not able to take up our last offer.
You say work commitments. 99% of us had jobs prior to coming to VS, but after we were offered the job, we resigned and therefore no longer had "work commitments".
At the end of the day the answer is still simple. Reapply, and see what happens. But have a good explanation ready.
Good luck!