What are you using as a lightest possible flashlight with the features you need? I have an Olight S20R Baton (2.5oz plus 1.5oz battery), and I'm looking to shave an ounce or two.
rechargeable, preferably 18650 battery (1.5oz for battery)
550lumens, selectable (550/120/5/moonlight)
recessed switch on rear end
seven nights between charges (the olight is more than enough)
Basically a lighter version of this with a recessed button on the end:http://www.batteryjunction.com/olight-s20r-xml2.html
I'm not considering head lamps at this time.
I also have a keychain LED as a backup.
so, what are you using?