I think by the time you spend the energy to try and find the part then go hunting for a similar size CampI BB could have already been riding the bike with a Phil BB in place for about the same investment.
If it was an actual bearing that was bad I would say look for a good bearing supply shop and see what you can find but not something like a CampI bearing sleeve.
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“One morning you wake up, the girl is gone, the bikes are gone, all that's left behind is a pair of old tires and a tube of tubular glue, all squeezed out"
Sugar "Kane" Kowalczyk