Given that South Dakota has announced they will be leaving the Great West, and North Dakota likely isn't far behind them, I'm wondering if the Great West's future is really in the Southwest.

Here are the remaining Great West schools:
Utah Valley
Houston Baptist
UTPA
Chicago State
NJIT

Here are the current Southland schools:

West - Texas A&M-Corpus Christi, Sam Houston State, Stephen F. Austin State, Texas-Arlington, Texas State, Texas-San Antonio
East - Lamar, Central Arkansas, Northwestern State, Southeastern Louisiana, Nicholls State, McNeese State

In all likelihood, Lamar, Texas State, and Texas-San Antonio will ultimately be playing FBS football and be leaving the Southland.

New Orleans and UALR have not expressed any desire to leave the Sun Belt, but being the only non-FBS schools in the conference may lead (or force) them elsewhere.

We start by the Sun Belt taking Texas State and UTSA, and the Southland replacing them with New Orleans and UALR. The Great West adds D-I newcomers Grand Canyon, Central Oklahoma, Oklahoma City, Dallas Baptist, and Tarleton State.

Southland, 2015:
West - Texas A&M-Corpus Christi, Sam Houston State, Stephen F. Austin State, Texas-Arlington, Central Arkansas, UALR
East - Lamar, New Orleans, Northwestern State, Southeastern Louisiana, Nicholls State, McNeese State

Great West, 2015:
Utah Valley/Grand Canyon
Houston Baptist/UTPA
Chicago State/NJIT
Central Oklahoma/Oklahoma City
Dallas Baptist/Tarleton State

After everyone has had five years together, the Southland sheds two non-football members for two football-playing members. By this time, Lamar has an FBS home, NJIT has found a more regional fit, and Chicago State replaces Oral Roberts in the Summit.

Southland, 2020: (all 10 members play FCS football; *counts towards 6/5 rule)
Sam Houston State*/Stephen F. Austin State*
Texas-Arlington*/Tarleton State
Central Oklahoma/Central Arkansas*
Northwestern State*/McNeese State*
Southeastern Louisiana*/Nicholls State*

Great West, 2020: (no footall-playing members; *counts towards 6/5 compliance)
Texas A&M-Corpus Christi/UTPA*
Houston Baptist*/Dallas Baptist*
Oklahoma City*/Oral Roberts
New Orleans*/UALR*
Grand Canyon*/Utah Valley*