Hi:
This is an outlandish story and like you I would also question whether or not these names are fake. Alton, IL? I think not...unless Phyllis' aunt lived there and she skulked off to have the baby. I searched all over for Phyllis in CO and you have probably seen the one in Aurora, CO, that looks like a close match, but Sullivan is her married name. The only other thing I can think of to break this wall down is to actually check both the year books for Stanford for all the possible years this Ziegler guy could have been there (he may have been a freshman or senior then so the span of time would need to be at least 1952-59) AND in case he attended but did not graduate, call registration and tell them your story to who ever will listen and ask them to check the records. I'm betting they will, especially if you call over the summer break when things might not be quite as busy as usual. I'd just keep telling my story until I got someone who would listen.
Another idea is if she died on the date of the birth then I would call VitalChek and ask them to go to Springfield, IL in search of her death cert. You can typically order a death cert from them online but I always call them because I usually have extra instructions to include, such as she may have died a day or two later and be sure to have the person who goes for me and is standing there to mention this to the clerks who are searching the records. Their url is:
https://www.vitalchek.com/Also, you sound keenly interested yet frustrated. Have you considered using your autosomal and Y DNA to track this mystery down? There's a nifty online article that explains it all at:
http://www.geni.com/blog/dna-testing-for-genealogy-getting-s...Let me know what you find out or want to try the DNA option and I'll try to help you. I'm a volunteer adoption researcher with 30+ years of genealogy research experience.
Best of luck,
Terri