I have had my finished high-power headlight/taillight system wired up for a few weeks now and it is working like a dream - highly recommended!
First I must thank InsanityIdeas for considerable help on the rear light, and system wiring! I'd never used a soldering iron before this, so I couldn't have done it on my own
First up, the front lights are stock Ay-Ups, sufficient to ride at my top speed on unlit roads (bear in mind I have a fixed wheel, so no 40mph descents!):
Although very functional, I also like the fact that the cockpit is extremely clean and uncluttered. (You can also see my recently re-wired 'European style' front brake):
In my spare bar-end, I have mounted a rocker switch which controls *front and back lights* simultaneously. Fingertip brake light is a reality!
If you take a look at the *first* picture again, you'll see that I hand-made a custom cable which brings power, and the switching wires, forward from the pannier rack in one neat line. Although I was afraid of making anything for road use myself, it does end up being exactly the right length and application! Another view:
At the rear, I have my 'homebrew' tail light (I've posted a long topic about this before). It's sealed with hot glue and has been working without complaint for several hundred miles, through some atrocious weather.
Not pretty, but *very* functional. The lenses are elliptical (wide but short) so the side visibility is great yet it doesn't point straight back into drivers' eyes.
Still, I have a backup blinkie Superflash 'just in case'. I haven't had to use it yet, except when it rains and short-circuits to flashing mode (ironic that of the two, the 'professional' light leaks!)
I put together a junction box to hold the very simple circuitry which places the batteries and lights in parallel, and introduces the switch. It's plastic and hollow, weighs about 30g:
Both the main lights are wired up in a common circuit and can be driven by just one Ay-Up battery. However I have built a 'spare' connector into the circuit allowing a second battery to share the strain:
Notice how the sides of the rack remain clean for attaching panniers (which are needed for the commute). When it comes time to charge, I just swap the battery cables from junction box to charger and forget about it:
Sweet!
I'm very happy with it and hope this might prove useful to someone, somewhere who fancies scratch-building. I'm happy to answer any questions.
Now, about that dangerous overtaking this morning...
The gold Ayups certainly look nice and bling! 
What is the run time with both front and rear lights on?