I have a bar mounted off/low/high switch for my X2 HID. It's never on when I start the bike though I have knocked it on a few times while the bike is off and ended up draining the battery.
It's not tied into the ignition yet but that is something I would like to do. I usally end up knocking the switch when loading the bike into a truck. Sucks arriving at your destination with a dead battery.
I did a 3+ hour run yesterday with a single light on the whole ride and with both HIDs running for the last hour after dark. I didn't run into any battery issues and had no trouble starting the bike at any time. We were stopping fairly frequently as well.
2011 Riff-Raff - Go Jonah