Recently I've seen some tactical flashlights advertised that have both LED and Xenon lighting elements built in. The user can have normal "penlight" type illumination without putting much of a drain on the batteries, but can easily switch on the high-intensity beam if it's needed. This seems like a great idea. Are any of you carrying/using this style of light? I'd be looking for one that could easily be carried in/clipped to a pocket, so I probably wouldn't want to go any bigger than a 2-lithium cell model (like the size of a Surefire Executive). Additional information (and sources for good deals) would be welcome.