This is a phrase I somehow remember from when I was young (60s-70s). In my mind it means "crazy in the head" and is somehow related to some Yiddish expression words. My family is from Europe, but no one ever used Yiddish, only German. When I use, most people seem to know what I mean, but on one knows the origin or if it really exists. Can anyone help? Thank you.
Ish Kabbible was an entertainer in the forties/fifties, I think. The word RedRaven may be looking for could be "meshugganah" or "meshuggah" or Yiddish for crazy.
Here's what I found at UrbanDictionary (their definitions are a bit different from the ones previously mentioned in this thread):
http://www.urbandictionary.com/define.php?term=ishkabibble
I don't put much faith in UrbanDictionary - there's better info elsewhere.
And thinking it over, I don't believe "ishkabibble" has a Yiddish meaning - it may be mock-Yiddish, or just gibberish.