Fallows found a chart (click to enlarge):
What states might look like if, as with Congressional districts, their borders were periodically redrawn to reflect population changes...This map is by Neil Freeman from FakeIsTheNewReal.org. It's based on a division of the country into 50 state units with more-or-less equal population -- 5 to 6 million apiece -- and preserving existing boundaries where possible. (As with the new state of "Missouri.") I love many of the other state names -- Lincoln, Joaquin, Tombigbee. My childhood home would have been along the border of Coronado and Mojave. In a reapportioned Senate each of these units would have two votes.
Yglesias imagines the consequences.