http://web1.ncaa.org/app_data/weekly...09WSBrpi1.html
That's the NCAA RPI site. I would go with that one. Check where LSU is ranked on this, the latest RPI. I believe the top 16 get #1 seeds.
I noticed a few Sun Belt teams in the top 64. This doesn't mean much as there are a lot of teams with very low RPI's that will get into the top 64 as they win the automatic bid from their conference. I think there are 34 automatic bids. Mississippi Valley is past the 100 RPI, they won their conference, so they get an automatic bid.
Another interesting site, but probably not as accurate is the Warren Nolan site.
http://www.warrennolan.com/softball/2009/index
What is interesting about the Nolan site is that the NFCA uses Mr. Nolan to determine their RPI. But, remember it is not the NFCA, but the NCAA that does the schedule. Anyways, check out the conference RPI. Sun Belt is not too bad.
Also know that Scott Farmer is one of eight chairmen for the NCAA in the regional scheduling. He said he was a Chairman of four conferences when interviewed on Cox Sports TV.