This may not be a he said/she said issue any longer.
One woman said that Cain upgraded her hotel room. We can go back through credit card records/hotel records and verify or deny this issue. I think this would be a key piece of evidence for or against Cain on this specific allegation (not the other ones leveled against him).
Cain said there was an internal investigation that said these charges were baseless. One of the Attorney's for the women said he was never presented such an investigation (and if it was done, it was not done by a 3rd party, but someone reporting to Cain). However, if an investigation was done, it could be released. This still may not say much considering it was not done by a third party (independent), but it could help validate Cain's story slightly.
One attorney said his client received a settlement. Whether this is a settlement or not is a moot point, but Cain's camp insists this was a settlement. The details of this "settlement" could be released to discover if it is a settlement or not.
There are some other unanswered questions such as why a woman who formerly worked for the restaurant association would need a tour of the offices where she worked before.
That sort of puts her story in question.