I tried ARP about 3 years ago and they didn't have them, at that time anyway. This question has come up before and I can tell you from personal experience that new inline headbolts are really hard to come by.
I'd like to see one of you enterprising young guys have someone make up a bunch to the proper specs and have them for sale. I think you'd sell them. A lot of the other engine bolts are available stainless and even Bowtie versions. I doubt you could retire on it but it would be fun and even generate a little profit.
