I agree, it's about time the factories did away with that useless and infamous white wire.
It was only good for 6 volt lamps and you were restricted to 2.5 to 3 watts. Not much light from 3 watts.
Go the battery route. It's reliable, cheap and depending on the amp hour rating of the battery you choose will give you good light for a long time and you can run high wattage lamps.
Do not try tapping into the ignition circuit. The blue wire will provide something close to 90 volts A/C at WOT, decreasing to about 60 at idle. Anything added to that circuit will seriously impact the way your engine runs, if it will run at all.
Tom