Here is a 'scorecard' by conference for 1996, the fourth year of data I have. I thought this might be useful info since the regionals are a major source of inter-conference and inter-region play that helps determine the relative strength and hence future seedings of teams from various regions and conferences.
Here is the 'histogram' of the success rate for the 1996 NCAA regionals.
------ wins ------
Conference Number 0 1 2 3+ champ comments ...
========== ====== === === === === ===== -----------------
SEC 6 1 1 1 3 the RPI was right
ACC 5 1 2 2 almost matched SEC
Big-West 4 3 1 2 last year was right
Pac-10 3 1 2 close but no cigar
SWC 3 1 1 1 waiting for Big 12
Mo-Valley 2 1 1 deserved respect
Big-8 2 1 1 Big 1
WAC 2 1 1 playin (but lose CS-N)
Big-East 2 1 1 seeded about right
Conf USA 2 1 1 seeded about right
TransAmerica 2 1 1 seeded about right
SunBelt 2 1 1 average (3 last year)
Ind - Miami,FL 1 1 they're back ...
Atlantic-10 1 1 good! (playin last year)
Southland 1 1 moment of glory
Big-10 1 1 surprise!
Southern 1 1 playin does OK
Colonial 1 1 automatic bid (wasted)
Big-South 1 1 automatic bid (wasted)
N Atlantic 1 1 automatic bid (wasted)
MAC 1 1 automatic bid (wasted)
Ivy 1 1 playin (wasted again)
Mid-Continent 1 1 playin (wasted again)
Ohio Valley 1 1 playin (wasted)
Patriot 1 1 playin (wasted again)
Metro Atl 0 -lost playin
MEAC 0 -lost playin
Midwest Coll 0 -lost playin
Northeast 0 -lost playin
SWAC 0 -lost playin
West Coast 0 -lost playin