Peppermint Extract

I have a recipe for homemade peppermint bark that, reasonably enough, calls for peppermint extract. Hah!

I have looked for this approximately 11 bazillion places (see NYC and NY Tristate area threads for details, if you're interested or local to Westchester NY and have thoughts about sources). Even Penzey's doesn't carry it.

I can't find it. I have Durkee's mint extract, which is a combination of peppermint and spearmint, but I really just want peppermint flavor.

While I haven't found extract, I have found peppermint flavoring, using oil as a base instead of alcohol. In particular, I've found Whole Food's house brand peppermint flavoring. Has anyone used this? Does it flavor things as well? Does anyone know what the replacement proportions would be?

Thanks.