2nd post... just registered... I was on the old board... I am a chaser... but haven't read any of this thread other than the last page.
I had decided to not chase that day (long story), but instead to get into OK for the next day's risk. I saw the Joplin storm from just W of Wichita. It didn't have an overshooting dome. It had an overshooting cone, which was taller than it was wide (at its base), and pointy at the top. Think "dunce cap". It was, I believe, at least 50% as tall as the rest of the storm, so if the flat anvil top was at 45K feet the top of that cone was over 70K. I thought one or two of you on this board might find that interesting.