I know that most of you guys probably think that I'm nuts...

[Spazito]

31. Interestingly, in trying to research whether it had ever been deemed illegal, I found...

that on November 12, just 3 days ago, the USSC has took up a gerrymandering case re Alabama:

"The U.S. Supreme Court on Wednesday takes up the thorny question of what kind of gerrymandering is acceptable, and what kind is not. The court is being asked to decide whether a 2010 state legislative redistricting in Alabama overloaded some districts with black Democrats on the basis of race or party.

Voting rights cases scramble politics and race. In this case, it is the Democrats who are crying foul because of what they call unconstitutional quotas. In contrast, conservative Republicans, usually critics of racial considerations, this time are defending government classifications based on race.

In the 1990s, the conservative Supreme Court majority, in a series of decisions, ruled that if a redistricting plan is motivated predominantly by racial considerations, it is unconstitutional. Those decisions came in cases brought by conservative Republicans who objected to the Justice Department's attempt to expand the number of majority black or Hispanic legislative districts under the Voting Rights Act in the South.

"Now, the tables are turned," says election-law expert Richard Hasen, a law professor at the University of California, Irvine. "It's the liberals and Democrats that are trying to use the racial gerrymandering claim to stop Republicans from packing reliable Democratic minority voters into a smaller number of districts."

http://www.npr.org/2014/11/12/363375057/supreme-court-case-seeks-source-of-alabama-gerrymandering

I'm not a fan of NPR as I think they have veered right in their opinions and coverage rather than being neutral but, in this case, given the OP subject matter, it seemed appropriate to use their site for it's information.

It seems there have been Constitutional challenges as to specific States' redrawing boundaries but not on the bigger question of gerrymandering.