You answer to why you didn't get hired is probably right here:
Yes the regional person had the final say. I only spoke to her on the phone, but she went out of her way to call me up when I didn't respond to her email so I figured I had a decent chance
(She wanted a phone screening, emailed on a Friday, and I came down with a nasty head cold that weekend, which is why I hadn't responded to her email - I was going to call her the Tuesday she called me
Not responding to a potential employers email because of a head cold, not a good idea, makes it seem like you are really not interested in working, or the type of person who is going to call in at the slightest excuse, not saying this is true about you, but what it might seem like to them (and what it would have seemed like to me). If you want the job, you should make it appear you will show up for work unless you are in the hospital.