I'm wondering if you're barking up the wrong tree here, Laz.
Is the trouble really that the voting system gives disproportionate power to urban areas, or is it that our culture has simply once again become more liberal? After all, you could also say that the current system over represents the groups that care enough to vote, at the expense of those who do not vote. (Comparison here would be against the "?ideal democracy" where every person spoke up and decisions were made by majority opinion.)
By that standard, these groups generally get power disproportionate to their numbers: the elderly, the educated, those over 45, non-Hispanic whites, and veterans.
It seems to me that the US democracy works just about right, since we generally get leaders who reflect the nature of the average American citizen. (As in: shallow, short term outlook, out for themselves, pushy to the point of aggressiveness, not that good at understanding other people's perspectives, etc.) Since we live in a democracy, wouldn't it make sense to either work to change the nature of the citizenry, or to move to a place that better reflects our nature -- as opposed to essentially gerrymandering to get the outcome we want?