How are the Streamlight TwinTasks? I don't have one, but I see they have a single CR123A cell xenon/LED unit for around $21. Looks small, and you have the LED backup in case your xenon doesn't work, maybe because you dropped the light and jarred the bulb.

http://www.brightguy.com/detail_int.php?Sku=STR51004

There is a two-cell model as well, bigger and brighter (and longer runtime) if you want that tradeoff.