The NCAA experimented with a height change during the week of the 1973 Final Four. I was at St. Louis University then, and they were the host school for the tournament.
Interesting that they were looking into it 50 years ago, when it wasn't really warranted anywhere close to what it would be today.
I'm not sure I'd go more than 10.5...you still want to see some dunks. Going to 11 or beyond would take a ton of guys off the rim completely.