Below is the only information I have with the date I came across it. I don't track the source:
Feb 2009 -- Montreat (NC) [NAIA] considering DIII.
Aug 2009 -- Clarke (IA) [NAIA] rumored to DIII
Aug 2009 -- Midland Lutheran (NE) [NAIA] rumored to DIII
Aug 2009 -- Nebraska Wesleyan [NAIA] rumored to DIII
Oct 2009 -- Purdue-Calumet [NAIA] rumored to DIII
Feb 2010 -- Iowa Wesleyan [NAIA] no longer considering DIII.
Clarke just moved from D-III to the NAIA recently.
Nebraska Wesleyan is D-III Indy, except for football where they play in the GPAC
There were 3 or 4 Nebraska schools looking at D-III last year and they all decided to stay. Doane(NE) was another one.