Regarding Apple's statement that the problem occurs in G3 Macs that have "Outrigger and K1 enclosures," Kevin Purcell writes that these terms were internal code names for the products. Outrigger refers to the desktop case (so named because of the swing out power supply). K1 is the mini-tower case (it's half of a K2 case, such as the one used in the 8600). This implies that the shut-off problem may affect all G3 Macs, not just the mini-towers. (Mini-towers may still be more susceptible to problems here because they are not Energy Star-compliant, while the desktop models are.)
As noted before, AppleVision monitors (and any other EnergyStar-compliant monitor) may turn off correctly at shut down in any case (although, this may mean the monitor is in "stand-by" mode, rather than completely off).