help,12 v circuit board with computer controlled switches

[Baxidur]

Hi

First off i'm new to this so please try to to flame me to badly for any ignorance of electronics on my part.

I'm trying to build a circuit that will fit in a 5 cm x 5 cm x 3 cm box, it will have a 12 volt powered usb connection and six individual wires leaving the box, each of the six wires leaving has the following requirements :-

1: the ability to turn on and off a 12 volt + power supply from a computer with binary code down the wire through a device then to a common earth.
2: the ability to register the voltage passing through in 1% increments of the 12 v's from 0-100% and send this information via binary code down the usb output. (i was thinking adc, but there may be better ways.)

Also the 6 wires need to be individually configurable on/off seperate readings and individually noticable 1-6 for the computer.

A way to individually fuse or resetable fuse the system would also be a bonus

Thanks in advance for any help and i'll try to check back here daily to answer any extra questions

Mark Nutley