Most of the Macs made 1993+ don't seem to go to black and white when the battery fails.

Correct me if I'm wrong, but doesn't the Q630 use the 4.5V battery, the rectangular one? It seems to be that all 4.5V battery Macs don't have depth problems.

The LC, LC II, and the II series (not sure on the IIvx as I've never seen a dead battery in one) all will go to monochrome. All use the 3.6V battery.

The LC 475 is an exception--it doesn't even boot with a dead battery!