App note from Analog Devices about ways to extend capabilities of their ADM106x supply supervisor and sequencer chip. Link here (PDF)
The ADM1062–ADM1069 Super Sequencers accurately monitor a number of input rails. The ADM1062–ADM1067 have 10 input pins dedicated to monitoring (VH, VP1 to VP4, VX1 to VX5) and the ADM1068 and ADM1069 have eight (VH, VP1 to VP3, VX1 to VX4). Each of these pins has two internal programmable comparator circuits. By programming these circuits undervoltage only, overvoltage only or undervoltage and overvoltage trip points can be set up around each monitored supply. These trip points are 1% accurate at all allowable voltages and across the entire operational temperature range of the devices.