I know that the original Celerons supported SMP. Whether they would support quad or only dual is something I don't know. My guess is, if the PII supported quad, the Celeron supported quad.
I hear that SMP has been disabled on the newer FC-PGA (Coppermine) Celeron, but have not confirmed this.
So dual PPGA Celerons should work.
4 Celerons might work, I don't know. I would try it. If quad Celerons works, good. If not, put the spare parts in some Intergraph Dual P-Pro machines (because they can be had for little money) and resell them.
Cast not thine pearls before the swine