Look for the AAA mag-lite to go LED soon if they are not available already. AA versions are already available with LED though unlikely to fit in the sheath kit we are talking about. Ditto what harmless says about the LEDs but I also like Stoney's idea of universal battery size for your gear (and also something universally available as well). On the flip side I have had an LED squeeze light clipped to my work keys for over two years now. Still running on the original battery. Still a bright light as well. To beat all it was a free giveaway so presumably a cheapo light. Go figure.

Update with a link to an LED upgrade for the AAA maglite solitaire.

http://www.led-replacement.com/lt-3.html

Kinda pricey though. You might want to wait and see if mag-lite doesn't incorporate an LED into their design soon.