Here's the MVFC teams who have made the playoffs in the last 15 years:
1995 - UNI
1996 - WIU, UNI
1997 - YSU (YSU won championship), WIU
1998 - WIU, ISUr
1999 - YSU, ISUr
2000 - WIU, YSU
2001 - WKU (first year in Gateway), UNI
2002 - WIU, WKU (WKU won championship)
2003 - SIU, WIU, WKU, UNI
2004 - SIU, WKU
2005 - SIU, UNI
2006 - ISU, SIU, YSU
2007 - SIU, UNI
2008 - SIU, UNI
2009 - SDSU, SIU
2010 - NDSU, WIU, UNI
So, every year since '95 we've had at least 2 qualifiers, with 4 in 2003 and 3 in 2006.
In 2003, there were 4 qualifiers due to a couple of teams in the conference being "down" and success out of conference. The teams and their overall records were SIU @ 10-2, UNI @ 10-3, WIU @ 9-4, WKU @ 9-4.
UNI and SIU shared the conference title.
SIU - lost to UNI the last game of the season, then Delaware the first round of the playoffs
UNI - lost to Iowa State and WKU, then Delaware in the second round of the playoffs
WIU - lost to that year's FBS national champion LSU, SIU, UNI, then Colgate in the second round of the playoffs
WKU - lost to Auburn, WIU, SIU, then Wofford in the second round of the playoffs
This year, there's also 3, but we have an expanded bracket (now 20 teams vs 16 previously). If we were still at 16, there's no way NDSU would have made it this year, and WIU would have been severely on the bubble. I would imagine that with the expanded playoff field, we'll most likely see 3 nearly every year.
I don't know how that compares to the Big Sky, I know that Montana had made the playoffs every year in there up until this year. If someone more familiar with the Big Sky members wants to look it up, I used this as reference:
www.fcspreview.com/history.html