I used a magura brake lever with an integrated brake light switch. I got it on ebay for $31.00, but I had to pay another $12 for the switch, and $9 for the cable adjusting barrel. Pretty pricey, but the magura lever is probably the finest built product on my whole bike. Heavy duty with a bent arm for maximum cable travel. I can really pull hard on my front drum brake with this lever. I looked on ebay right now though, and that seller does not have any listed.
For the light, I used an old Ford model A tail light with license plate light underneath that houses an 1158 dual filament 6volt bulb.
I have a build thread
here where you can see my brake lever with the brake wires wrapped around the brake cable, as well as the tail light assembly.
Gilbert