doesn't explain the lack of tail lights..
Without looking, I'd start saving..I reckon something has gone chernobyl under the dash.

My first thought would be the main fusible link it can't be an earth problem because it has dropped everything out. The main fusible link is what suplies 12V to the fuse block

What about the regulator? do you have another one spare you could try. If its not working proply it wont supply power to the fuses from memory.

How do i tell if a fuse has had it's day?

I think datb110 might be onto it. Mine did the same thing a couple of weeks ago.
First the charge light came on every time i used the blinkers, kickdown, or reverse. Then nothing worked. It looked like everything was in order under the dash. So i figured it was the regulator.
Haven't been bothered to swap it yet, But im pretty sure its the culprit.
Blown fuses and melted wiring tend to give themselves away pretty easily. Plus mine is stock without any accesories or wiring chops ect.

I had the same problem with my b10 on the weekend and it turned out to be dirty connectors in the fuse box. I lost brake lights, tail lights, blinkers, heater fan, factory tacho and head lights oh and the radio turned on but wouldn't work. I took all the fuses out and cleaned all connectors and now everything is working fine fine. good luck

Thank-you to all who replied. Problem fixed. All i needed was that push in the right direction. Not sure exactly what the problem was , but , rewired that line from the + battery terminal with fresh gear and gave it a full set of new fuses & cleaned up the fusebox. w00t!