Big Nick also have information on his website see link#2

Also Shure and AKG has a very good clip on for the accordion.

There are also very good ones from Shure(Shure 98) and AKG(516 or 418)
Link#3 gives you some examples.

I'm not sure, but I thought that Junior Martin made the old fashion front Mounts?

Can anyone post some photos of his/her Audio Technica mic clipped onto the accordion? Thank you!