Actually the only difference between winchester and newcastle is the die? (Temp is lower on winnies)
I have a 3500+ Clawhammer Yes.. for socket 939 and yes you can get them.. They oc quite alot.. they have better memory controllers than almost all of the winchesters.. They are selling on Newegg.. i had mine a few months back, dont know if they still sell em now.. But my friend in america got it and tested it before sending it to me and he got 2.7ghz stable on air, not bad eh?
if your going to be using extreme cooling DO NOT bother with a winchester, mine kept freezing up constantly (excuse the pun) because it couldnt handle the low temp.. So now im left with a wasted 3500+ winnie which will probably end up on ebay if i can be bothered
go for the winchester if you can i would suggest the vince core instead. but you may have to flash your mobo to support it, if not get one that already been flashed form like newegg.com, i know he DFI NF4 Ultra-D all support them now.