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?

Note that in both the problematic Answer and my example attempting to mimic the same context more briefly, the writer doesn't know how many there are. There may be one, more, or even none.

Getting even more specific, the writer might have an opinion on how many there might be, and wish to convey his leanings by choice of verb form if language allows this to be done succinctly.