Just checked the output of a B&W's 'front panel' component. While running and tapping just at the connector's interface to the MB one B&W showed 23.1v. That's probably enought to start up a Gigabit/quicksilver class MB.I have no idea what sort of current it can produce, but I'd question if it would run an ADC monitor.

Many ATX PSes have a 4 pin connector dumping 12v which looks like it would fit the P4 connector on these MBs as well.

Some newer ATX PSes even have a 24pin connector which would fit the socket, though some tedious rewiring would need to be done.