I spent a little time researching this but can't find any source for historic enrollment numbers at all of these schools.
I found articles referring to Billy Packer's Wake Forest team (1962) and that could be true, although current enrollment at Wake is 4400 (undergrad). Jacksonville claims to be the smallest school to play in the championship game (1970) and their current enrollment (3400) would make them smaller than Wake now, but then? Another article (on Xavier, currently 4000 undergrads) suggested it would be the smallest "since 1979", a year in which Indiana State's Larry Bird team was the smallest (current ISU undergrad enrollment is 8000+). The other participants that year were Michigan State, DePaul (over 20,000) and Penn (notable less for its size than it's no-scholarship Ivy Leageu credentials), so I'm not sure why they chose that reference.
I haven't been able to prove, therefore, that St. Bonaventure was not the smallest when it made the final four in 1970 (on Bob Lanier's big shoes and soft touch, but sadly with him on crutches). Current undergrad enrollment (2400) is, I think, only slightly higher than it was in 1970 (when they beat Davidson in the first round). I will, nevertheless, root for Davidson to establish the new mark this year.
Providence College played in two final fours and they are under 4,000 in enrollment. I believe Holy Cross also played in one back in the day and they are small as well.
The NCAA Final Four was played in Denver in 1990.
It was butler with a little less than 2,000 students.
The cast of NCAA Final Four - 2011 includes: Charles Barkley as himself
In 2008 this was the first time in the history og Men's NCAA basketball tournment were all four number seeds have had it to the final four. In 2008 for the first time in history of the Men's NCAA basketball tournament all four number one seeds reached the NCAA final four.
Penn in 1979.
The "Final Four" are the four teams that win the regional championships in the NCAA basketball tournament, thus becoming the final four teams in the tournament.
The average score of the NCAA final four games from 2000-2006 was: 81-56.
This year's (2008) Men's NCAA college basketball Final Four is being held at: San Antonio, Texas.
Indiana U in 1975.
The Final Four is the national semi-final of the NCAA Tournament featuring the winners of the four brackets, which decide who play in the National Championship
The Final Four are the last standing teams of March Madness in either NBA or NCAA basketball. There are two final games involving the Final Four, two games involving two of the Final Four teams. The two teams that win each of the Final Four games move on to the National Championship, the final game of the season (for NCAA).
Through 2013, Kentucky has advanced to the Final Four of the NCAA men's basketball tournament 15 times.
The NCAA Final Four begins April 5th and ends April 7th. The games will be played at the Alamodome in San Antonio, TX.
NC State has made 3 NCAA Final Four appearances (1950, 1974, 1983).
The 1996 NCAA men's basketball tournament Final Four was played at the Continental Airlines Arena in East Rutherford, New Jersey.
The 2010 Final Four were Connecticut, Butler, Kentucky and Virginia Commonwealth.
2011 Womens Volleyball Final Four -- San Antonio, Texas
1975 - The Indiana Hoosiers lost in the Mideast region's final to the Kentucky Wildcats.