After following the forums here and at Apple's web sits, it's my guess that long(er) delivery times on the 27" iMac are primarily due to high demand, and not due to a production line retool.
Demand is probably high because:
1. The 27" iMac was recently released.
2. It's right before Christmas.
3. The new iMac has garnered good reviews in the mainstream Apple press (e.g. MacWorld).
4. It's perceived as representing good bang-for-the-buck (in the Apple universe).
5. The showroom models are flat out gorgeous (sexy).
Witness the large number of knowledgeable enthusiasts (e.g. active MacRumors members) who purchase the thing despite the fact it's revision A and despite the flurry of complaints we're seeing. I'm anticipating getting two myself, one to replace my wife's aging iMac, and one to replace my old G5 PowerMac workhorse. The i7 would end up providing me approximately 90% of the productivity of a somewhat comparable octo MacPro system--at half the cost!
I predict that the ComputerWorld article (despite the typical circular Internet reporting) will lead to a little more mainstream pressure for Apple to publicly and/or quickly address the current issues.
I also predict that a combination of software/firmware tweaks will fix the flicker/ticking problems and that the cracked glass handling/packaging problem has already been fixed. The "yellow tinge" problem may be different in that it may involve some inherent property of the panels or interaction between the panel and other hardware. (Do LCD panels interact with thermal/RF/magnetic sources? Any LCD engineers out there care to weigh in? I prefer not to experiment on my own monitors.

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Since (in my opinion) the yellow tinge is the only real "show stopper," I plan to go back to Best Buy and check out the showroom model again. To be honest, when I first saw the posted picts of the yellowing problem, I thought I would need to stop by my friendly neighborhood optometrist's office on the way home. It turns out that the "suboptimal" LCD monitors hooked up to the "suboptimal" PCs at work may have de-emphasized the color difference. When I got home and fired up the ACD, I could indeed see the difference (whew).
The gradient, especially if it is minor and/or rarely visible (i.e. only visible under rarely-encountered circumstances), may not be an issue to me, especially since my job does not rely on exact color accuracy. Hence the trip back to Best Buy.
Maybe I should leave my VISA at home, just in case I get "the urge"...