Only the 1.2 Celeron has the Tualatin core and uses the FC-PGA2 style connection. Up to 1.1 is still the FC-PGA connection according to http://support.intel.com/support/processors/celeron/24766.htm
which means the 1 Ghz only has a 128KB Cache.
I have bought plenty using pricewatch prices, you may have to pick and choose your companies a little but you should be able to buy the 1Ghz for less then $80 and then about $10 for shipping.
I too would love to see someone figure out the fastest 100Mhz FSB chip. I think a dual between the 1Ghz Cel and 800Mhz PIII would be interesting (since the 1.1 and 850 are harder to find and cost more) to a lot of people trying to upgrade older boards without the ability to go beyond 100Mhz FSB.