Not a totally crazy idea.
Are you doing a lot of these?
The lathe idea could work but there is a but.
Your slitting saws are going to be spaced 0.06" by using spacers. (How is that for an obvious statement? Wonderful how smart one can be with the help of a glass of wine.)
Seriously; your arbor will have on it 101 slitting saws separated by 100 spacers with two end flanges and a nut on one end. The slitting saws are no doubt parallel to within fractions of a thou. It is essential that your spacer washers are similarly parallel. If any of the spacers are not perfectly parallel (I know perfection is impossible but you are going to need it here.) when you tighten the nut and compress everything any out of parallelism in the spacers is coverted into a bend in the shaft.
I harken back to the good old days of setting up horizontal milling machines with spacers and cutters on a long arbor. It was possible to introduce a bend in the arbor because a spacer had a dab of grease on one side. The grease would not totally squeeze out and the minuscule residue was the same as an out of parallel end on the spacer.
I suspect if extreme accuracy is required you may need a dedicated machine with fewer cutters making multiple passes.
An open mind is a virtue...so long as all the common sense has not leaked out.