Definitely check the FS/FT forum and make a post as well. I checked E-Bay and the only one even coming close to a Northwood was actually the Gallatin based Extreme Edition.
Newegg used to have them, last I saw one was about two weeks ago, there gone now though..... If you can't find onw look back at newegg as they might start selling them sometime, or maybe in the refurb section....
It's all a roll of the dice when it comes to overclocking. Some chips will clock great, some others might not go 10% over spec speed. The 3.2 is the least eager overclocker of my 3 Northwoods, but it still does 3.8 or so while remaining completely stable on just a little extra voltage(1.575).
My chip is probably a bit exceptional, but I would hope most retail 3.2 Northwoods would hit at least 3.6 on the right gear .
I have been fortunate enough to find a 3.4C ES on these forums. You should give a try in the there also as I guess some people wish to upgrade to LGA775 and PCI-E (or AMD) and would no longer need them. I visit the FS/FT daily and I see them from time to time.
I'm also looking for a 3.4 chip, but i'll most likely end up getting the prescott, that cpu and a 6800 ultra should breathe new life into my aging gaming box for at least a year