The interesting part of Vorlon's analysis has little to do with the Presidential preferences of the states. The Reagan era cemented the Republican presidential majorities in the South, for instance. However, the 80's continued to see Democrats elected to Congress from those states that supported Reagan's national agenda.
The changes to Congress came in two waves. The House saw its party realignment to match national policy occur in the 1994 election. There have been relatively minor changes in the House since then, despite three presidential elections and two off-year cycles. Barring a significant change by one of the two parties nationally, there doesn't seem to be any factor to move the House significantly in the next few cycles.
The Vorlon's analysis addresses the Senate. One interpretation may be that this is the last branch to feel the Reagan, then Gingrich, revolution. As noted, the Senate is slow to change, by design, and isn't affected by decennial census results.
The House is a really different kettle of fish.
In almost all the states there is enough of a division of power that the states didn't get gerrymanderd to help any one party after the 2000 census (Texas being the notable exception) - but the degree to which they were gerrymandered in a bi-partisan Incumbant protection effort is rather stunning.
Some rather stunning numbers:
House races decided by less than 10% => 18 out of 435 (under 5%)
House races decided by less than 5% => 9 (barely 2%)
The GOPO has had a 230ish to 205ish majority now for 6 straight elections and the "stability" is due almost exclusively to the gerrymandering.
There are about 210 "safe" GOP house seats and about 190 "safe" Dem seats in the House,
These are seets where it would take a combination of scandal, plus a strong and well financed opponent to knock the incumbant out.
Both sides have lots of whiz kids with computers and the post 2000 boundries in the House are designed to protect incumbants to a degree that is just stunning.
The Senate is where the real "action" is - you cannot, after all, Gerrymander an entire state 
No question that in states like CA and IL the pro-incumbent gerrymanders were striking. It's interesting that a in IL one could have had a fairly ungerrymandered map that still would have elected the same Reps, but they would have had to work a bit more at it. It also would lead to a real contest when the seats opened up.
It would be interesting if the Congress acted like they used to and set rules for districts. Some of those rules included the elimination of multimember districts in 1842. Congress has avoided the phrase "compact" in defining districts, but a simple rule like requiring districts to not split Census Tracts, would be a powerful tool to eliminate the worst gerrymanders.
Of course, given that big states are using gerrymanders to protect the incumbents, a weakening of that power seems unlikely. However, much like in 1842, a few states moving like TX, might prompt some rule making. At that time AL switched to multi-member districts to favor Democrats, but other Democrats around the country became worried that the Whigs could respond in some northern states. The prospect that current procedures can turn out incumbents might make a compelling case for some now serving to enact protective rules.
