Some ideas: (sorry if any of these were mentioned earlier)
1) Combine the Dakotas
2) Make a coastal state from San Fran to Wash. State
3) Expand West Virginia into eastern Kentucky and southwestern Virginia
4) Combine northeastern Ohio with western PA
5) Combine Central PA with Western and Central New York
6) Attach western Iowa onto Nebraska.
7) Give Mich.'s Upper Peninsula to Wisc.
Attach NH's western counties to Vermont
9) Create a state from eastern Texas, eastern Okla., northwestern Arkansas, and southwestern Missouri
10) Make south Florida a separate state
11) Attach Fla.'s western panhandle to Alabama
