Thanks Mariush for the info. about new stock on the LM399H#PBF at element 14.
I used the complete part number for a search via Octopart.
Really surprised to find that several trusted vendors sell the lm399 made by Linear Tech.
Digi-key has a bunch of them at about 10 bucks USD a piece. Happy, happy, joy, joy!
I just made the assumption that the lm399 was out of production because it was such an old part
and when searching for the part on the web, I assumed that I missed it on the L.T. product site
because I didn't use the complete part number that L.T. uses.
My bad.
I'm going with Digi-key, but thanks for the tip and the offer.
You saved me a lot of head banging.