While adding to an Answer to this question, I needed to use the above phrase, and I suddenly realised I was unsure whether to write "is" or "are".

• There is more than one way to skin a cat.

• If there are more than one species of cat, we will flay each species differently.

I don't think that second example above sounds quite right to me (disregarding the meaning - sorry!), but in my original Answer I felt "is" would have been even worse.

Is "are" always wrong here? If so, what exactly is the rationale? If not, is there a case where it's unquestionably preferred – and why is that?