I just returned from a business/trade gathering and did some homework for you. I talked to 38 fellow Jews, mostly from Washington D.C., Baltimore, Philadelphia, New Jersey and New York. (in other words Northeast Establishment Jews) and all were willing to answer my questions about their vote. The following is who they voted for in 2000 and 2004. Amazing, here it is...

2000)
Bush 6
Gore 30
Nader 2

2004)
Bush 18
Kerry 19
Nader 1

Whoa! All but 3 were somewhat discreet about it and did not "chest beat" in public about it (2 were more enthusiastic then I). I think your "secret source" is not only right, but from the above I actually believe the shift was even stronger in some of the "I-95 Terror Corridor". Now this group was decidedly male and businessmen, but I think if we ever truly dig to the bottom we will find a very big shift in support of historical proportions.

Snickering about the Kerry buttons in Hebrew. Let's just say they could have spelled "K-R-Y" several different ways and boy did they pick the wrong one.

More agita about the Jewish vote here. More unlikely Bush voters here, and follow the links back to other entries on the topic.

UPDATE: Followup to Samuel's informal poll:

I have since talked with a person that used to do such work for me and I was flabbergasted by what was revealed to me. In a poll he took, the Jewish vote according to him (and he is a Democrat) MORE THAN DOUBLED! In other words, what was around 20 percent according to him increased to over 40 percent! This also was a scientific poll of more than 500 people. Again I am flabbergasted and wouldn't believe it if I didn't know the source. I asked. Why is this not being discussed? His reply, "It is a 'dirty secret' they want to keep a secret, don't expect them to talk much about some of their internal polls, they aren't very encouraging."