I am reaching out to Intel labs. I will report back if I find out anything interesting. I dont currently know of anyone using their foundry for BTC ASICs.
Edit: haven't heard back from them at this point
AFAIK Intel has never contracted out their fabs to anyone outside of the Intel family.
I can understand why - doing so inevitably leads to process IP leakage. One way it happens is from a customer pushing to get enough information so they can leak to another fab under the guise of "creating a 2nd source 'just in case'..."